Unlike old forums dedicated to a hobby or scene, on twitter people can talk about anything, and the only prerequisite for gaining attention is to open your mouth (type a sentence) and get a reaction, naturally saying things that get the strongest most emotional reactions becomes the way everyone talks on twitter.
Everything people say sounds the same. If you make one comment it can be blown up by thousands of users so people tend to just make the same arguments on all sides. If they begin to change on one or two issues their own followers on their side will attack them, so everyone basically just screams for their team.
Even when you aren't someone who spends time arguing and engaging in drama on twitter, the short post length gradually trains people to speak in little bird speech. Eventually it even makes users think like little birds.
Whenever I have to go on twitter for an actual reason, it doesn't take me long to feel disgusted with the world. It's not even to do with people's opinions or extreme things they say, it's the shallowness. I find myself getting shallow just looking at it; everything is either shocking and vulgar, or sickeningly genteel and twee on the big sites; there's no in between.