Some people would burn you at the stake for heresy of saying that cultures are not equal. That's what happens when moral relativism is encouraged and advertised, and yet, with just one simple metric of how far from non-aggression principle given culture is, it is so clear that in fact cultures are not equal. That's a fact. But the idea of "fact" is getting such a bad PR these days. Which seems like next stage of relativism: not only facts don't matter (just opinions), but facts are not... facts. There is nothing but opinions and no opinion is allowed to be better than others.

Like saying there were not 6 million Jews that died in WWII, can get you locked up

Facts should be defended with education, not prison. In my humble opinion :)