Webtoons is mostly straight stuff and their community can get toxic with gay stuff sometimes.
Twitter has a tendency to result in false rumor spreading, mass bullying, etc etc, all often in the name of a "political/moral purpose". Most likely due to the character limit and trending topics, making it quick and easy to spread half truths or half of a story, and if it gets popular it gets taken as fact.
The sites you mentioned aren't without blame or without groups of people disliking it just because you happen to like them more.
As for other points of view, tapas users are often respectful as long as you have a live and let live mentality. If, however, you go around saying you "identify as an apache helicopter" or say that homosexuals are sinners that should be burned to death, then no, you're not gonna be very well welcomed. And for good reason. I don't think it's a bad thing at all that bigots aren't welcome to come here and make people that are already dealing with a lot of shit at home feel even worse.