I really don't get this whole "I'm not Christian but I respect Christianity" thing. All religion is stupid, but religions like Christianity and Islam preach that if you don't worship a god that is literally a mass murderer, then you get punished for eternity. These are not religions that produce a healthy mindset.
I don't know if Jesus ever really existed, but if he did, he wasn't a great teacher or spiritual leader. He was probably mentally ill and preached tyranny.
Whether or not you respect Christianity, there is exactly zero percent doubt that Christianity (along with the civic republicanism of ancient Greece) is the very foundation of western civilization in ways we generally do not even think about. In ethics, literature, art, politics, philosophy..
Whatever flaws Christianity has in practice, it was arguably the first religion that imbued every one with a sense of equality. The soul of a prostitute was equal to the soul of an emperor in the kingdom of heaven. The ethical traditions of the NT and the implication of spiritual equality was a profound transformation from the pagan religions of Rome. Whether we realize it or not, that theoretical sense of equality has had trickle down and intangible effects throughout Western history.
I maintain that virtually all of western culture, thought, art, philosophy, and ethics has been touched by Christianity, and we are all touched and informed by it, even if only by osmosis.
Yes, everyone knows many terrible things were done in the name of Christianity. Lots of terrible things have been done in the name of science too. But I for one am generally appreciative of western culture, western civilization, western thought. And if I am honest with myself, I have to admit that my intellectual, cultural, and ethical tradition was born in the crucible of Greek antiquity and early Christianity.