There doesn't need to be. All rights have limits including Free Speech. For example, you can't use free speech as "fighting words" and you can't use Free Speech to cause public disorder (shouting "FIRE" in a crowded theater). Using free speech to intimidate people would fall under the "fighting words" limits. So it would be a pretty high bar to prove that prohibiting speech for the purpose of intimidating others to act or behave in a specific way would be a violation of free speech.
Say for example, If I approach you in public and say to you "If you don't vote for John Q. Republican I'll kick the shit out of you." and I get arrested for intimidating you (assault), pleading that my threatening and intimidating words are protected as Free Speech probably wouldn't pass legal muster and you'd probably be convicted of assault. People are arrested, charged and convicted for threats and intimidation (assault) all the time.
Not true. You are exaggerating the limits on free speech. No speech is illegal in itself, but government can restrict certain types. That includes obscenity, threats, slander, and fighting words. These can be limited because the type of speech that the Constitution seeks to protect is speech about public issues.
But fighting words is very limited. If I am in your face yelling personal insults (not political speech) at a specific individual that would want to make a reasonable person lash out in reaction a police officer can ask me to stop to prevent imminent (immediate) violence. If you hit me before the officer intervenes, my speech was not restricted and it is no longer a free speech case. You committed assault but you may have a defense due to my actions.
45-5-203. Intimidation. (1) A person commits the offense of intimidation when, with the purpose to cause another to perform or to omit the performance of any act, the person communicates to another, under circumstances that reasonably tend to produce a fear that it will be carried out, a threat to perform without lawful authority any of the following acts:
(a) inflict physical harm on the person threatened or any other person;
(b) subject any person to physical confinement or restraint; or
(c) commit any felony.
(2) A person commits the offense of intimidation if the person knowingly communicates a threat or false report of a pending fire, explosion, or disaster that would endanger life or property.
So, it is only intimidation if the person uses threats to make a person commit some act or not take some action. A flag, symbol, or even threats do not constitute intimidation.
Your example of "If you don't vote for John Q. Republican I'll kick the shit out of you." and I get arrested for intimidating you (assault)" probably meets the elements of intimidation (but it is not assault). That example is very different than waving a flag or symbol because it contains none of those elements.
I can make a speech in a public park and tell a crowd they are all stupid, fat, and ugly and types of offensive things and unless that crowd shows immediate actions that threaten violence is protected speech. And even then, my speech can only be restricted if there are not enough police to handle the crowd. Their threats are the crime, not my speech. But police can stop my speech if that is the only way to prevent violence.
Even threats must be strict standards. They must be serious and I must be capable of carrying it out. A guy was convicted of threatening President Obama by writing on a Yahoo message board "Obama is going to take a 45 to the head" and calling him a racial slur. His case was overturned because he did not threaten to shoot the president.
Another case was was convicted for saying "if LBJ comes to town and I get my sights on him, I will shoot him." It was overturned because it was based on a condition that might never occur.
And, you can advocate anything you want--sex with minors, overthrow of the government through violent revolution, etc. as long as no action is taken toward that goal.
