I am curious why the allowance of anti-LGBT viewpoints is so controversial. As stated above, all of the basic rules of civility are still being enforced.

Because the people that are calling everyone else "transphobic" and "fascists" and "nazis" can't see that they're the ones being fascists by trying to censor all differing views. They can't handle having people with different opinions and viewpoints, often because they can't actually defend their odd views themselves, so they prefer to kick up a stink and have all different opinions banned.