A legitimate government interest is only required when a justified government interest seems to conflict in some way with an unlimited interpretation of a right, i.e. when rights come into conflict with other rights or some deeper issue of justice. If the status quo were equal because, as you said, all men are free to marry any woman they want, and vice versa, then a "legitimate government interest" is superfluous. When something isn't protected by a right, the government is free to act, within its power. As Thurgood Marshall once said, 'The Constitution does not prohibit legislatures from enacting stupid laws.' However, if that were the case, then racial miscegenation laws, which are able to use the same logic, don't need a "legitimate government interest" either, as they are not conflicting with the principle of equality, since, as a gay man is free to marry any woman he wants, a black man was also free to marry any black woman he wanted.
Are you attempting to back off of your earlier statements, to move the goalposts, and are now claiming that even though the situation isn't equality, and was not equality in the case of racial miscegenation laws either, a ban on gay marriage is still justified because there is a "legitimate government interest" here where there isn't in the case of racist marriage laws? After all, I suppose, sex-segregated bathrooms are one violation of equality that is nevertheless supported by a legitimate government interest. So is, for instance, the draft.
Or are you going to stop sidestepping my rebuttal of your argument by making a second argument that would be superfluous if the first one were true, and enlighten me as to how the first argument, as used in the justification of a ban on gay marriage, is significantly different in form from the argument used in justification of racial miscegenation laws? Or are you simply confused, and throwing out any random argument you can find with little comprehension of how they fit together?
If you really think about your argument, that everyone has equal rights because gays have just as much of a right under the law to marry women as any other man is, it's really nothing more than a claim that there is a law, and it applies to everyone, thusly making it "equal". You could really use this logic to justify just about anything. You may as well say that there's nothing unequal about a law that, for instance, made it legal to shoot any gay you saw, because, after all, gays have just as much of a right to shoot gays as anyone else does. Obviously, this is not equality in any meaningful sense. Women are given the right to marry men, but men do not have a similar right to marry men. The two are obviously not being treated equally. The existence of a vice versa when it comes to men marrying women does not suddenly produce a state of equal treatment. It's also important this argument is not the one used to justify the lack of equality by actual gay marriage opponents, as it's obviously garbage for the reasons I have explained. It's little more than an equivocation that gets far more credit that it deserves in popular arguments simply because most people are stupid, and confuse equivocation with cleverness. Now, this is not to say that everyone necessarily has to be treated exactly equally in all cases, but I will explain that further below.
Now that I've expressed my discontent on that issue, I will, for the sake of it, address your second argument (which, again, is relevant if gays aren't being treated equally, and irrelevant if they are). Your argument seems to be an application of the rationality test, which is the default test used in regards to issues of equal protection and due process. The rationality test essentially holds that there is a "legitimate government interest" when the view in question is rational. "Rational" here being used in a medical sense, i.e. not insane. Obviously, almost anything is considered a "legitimate government interest" under this test.
It may seem bizarre that there is such a broad test applied in regards to the 14th, as other rights, such as free speech, are typically judged much more strictly, but there are good reasons for it. An overly broad interpretation would oftentimes simply defy common sense (for instance, sex-selective bathrooms would be prohibited), and the due process clause as well can be abused by the judiciary to involve itself heavily in the legislative process. This was most infamously demonstrated in the case of the lochner era court of the 1900's-1930's, where a set of social darwinist judges seemingly made up a "right to contract" out of thin air and applied it zealously, striking down pretty much any law (federal or state) that sought to protect the safety and well-being of workers because it "violated" the "right" of workers to work for less than minimum wage, in unsafe conditions, etc..., as well as the "right" of children to work. Naturally, corporations were cartel-like in requiring workers to sign such contracts as a condition of employment, so workers had little choice in the matter. But that doesn't matter in the social darwinist worldview. And that was the rational viewpoint that these judges held, a rational viewpoint that they decided to substitute for the equally rational viewpoint of the legislature had in ensuring decent working standards. This era of jurisprudence is so widely looked down upon that a verb, to "lochnerize", has been created and come into usage as a synonym for "judicial activism".
If you applied the rationality test to racial miscegenation laws, they would easily pass muster, because the laws were supported by a large amount of people who were not, in fact, insane, and utilized logic that was perfectly acceptable to them. However, in regards to certain groups, "suspect classifications" that are especially susceptible to discrimination, a different level of scrutiny is used, strict scrutiny. Under this level of scrutiny, virtually nothing is considered a "legitimate government interest" when applied unequally to these groups. Race was first considered to be such a class, and later, religion and national origin were added. This was the logic under which racial miscegenation laws were first struck down. There are also quasi-suspect classes which are somewhat susceptible to discrimination, and an intermediate scrutiny is applied to them, under which the courts more carefully balance the state interest with the susceptibility of the class to discrimination. Currently, issues of gender and the marital status of ones parents at birth are considered with this level of scrutiny. However, I imagine that homosexuality is likely to be added in the near future, as a federal trials court in North Carolina recently held that it is part of this class, and the case will likely make its way to the supreme court.
So, on that basis alone, your arguments must be taken with a grain of salt. You cannot merely state that there is an "interest" and expect it to stand under this level of scrutiny. I don't think I'm insane in stating that, when it comes to gay marriage, a significant amount of opposition is merely due to bigotry, and the non-bigoted sounding arguments against it are often quite flimsy and desperate. Am I really to believe that gays shouldn't be afforded at least an intermediate scrutiny when the laws against gay marriage would typically be soundly defeated without the support of bigots? Should a massed swath of bigotry be allowed to dictate away the rights of minorities by picking out a veil of (claimed) non-bigots to represent them in the courts, who make bizarre and desperate arguments in the courtroom that do not at all resemble those used in the popular campaigns against gay marriage (arguments which are largely legally meaningless)? The government cannot merely claim that gays are bad parents and call it a day, as under rational basis review, it has to at least provide some good evidence. And such evidence is largely not to be found. The government interest in "furthering procreation" is also suspect. It would perhaps carry more weight if there were any other attempts to limit marriage to those who can reproduce, or more heavily subsidize procreation on the part of the couple. However, such measures are curiously lacking. It is incredibly convenient, is it not, that the only time this excuse, er, I mean, "interest", seems to come into play is in regards to gay attempts to limit gays to marry. I also seriously fail to see how it does further procreation, since unmarried gays don't procreate at any greater a rate than married ones.
It's also important to note that there are certain rights that stem from the due process clause which are considered fundamental, and issues involving these fundamental rights are also judged using strict scrutiny. Amongst these fundamental rights is the right to privacy, which includes within itself a set of rights, one of which, the courts have decided, is the right to marriage. Could you please enlighten how denying a man the right to marry a man whom he happens to be in love with does not violate this right to marriage? Especially when others (namely, women) are given that right, to the exclusion of him? And, obviously, vice versa for women who marry women. You really can't bring the typical argument of maritial anarchism, that the next step is to allow people to marry animals or somesuch, into this. As you gleefully point out, these people are those who have already been judged ready for a marriage of some sort. You would not be expanding the pool of those who can marry one bit. You would simply be granting men the right that women now claim exclusively, and unequally, the right to marry men, and granting women a right that men currently claim exclusively, the right to marry women.
Anyway, there are clearly two very strong attacks on gay marriage bans, one from intermediate scrutiny, and the other from strict scrutiny. This is obviously a very strong position. Yes, previous challenges have failed, but that was only because the position was kind of shockingly new just a couple of decades ago. But society has readjusted surprisingly quick. Gay marriage has gained an incredible amount of grount, going from a position almost no one held to a position the majority hold. As time goes on, it simply seems increasingly obvious. I imagine the reasoning that judges used previously was heavily influenced by the amount of political and social pressure put on them to rule the way they did, so they had to construct some rather convulted logic to rebut it (judges aren't typically elected, sure, but public pressure does have an effect on their position). Now that the pressure has been lifted, and even started going in the reverse direction, I imagine that there will be little time until the judges choose to make the correction.