Alright, it's time to clarify some things. First I will make one thing clear:
Creating threads, blog posts, comments or anything else with the purpose of intentionally starting an argument (not a debate) or provoking people to start one is NOT allowed, no matter the subject.
"But-but muh free speech!"
You ARE allowed to have opinions on certain subjects but insulting a person or a group of people is definitely not allowed. First of all, it is a logical fallacy, using an insult doesn't help you win argument (look up "Ad hominem").
It has ALWAYS been against the rules to do that. If you can't find a better argument then having to resort to attacking the user with irrelevant insults, then you already lost the argument.
Acting aggressively or harassing another user is also not allowed.
These sorts of things happen all the time and cause stress for everyone, you, the users and the moderators/admins.
It would be a nice change of pace by seeing peaceful debates without people mocking others and just having friendly conversations. And plus, it's not like a few teenagers are gonna change the world by arguing about their opinions online, you'll grow out of it eventually.