For one, I think that the people you have put the "extreme" label on, are not as extreme as you think they are, and indeed could be quite agreeable when you'd seek them out and sit down with them over tea and try to communicate with them with more nuance than a 160 char message can deliver.

Yes, you will be able to find examples that confirm your statement, but they are an exceedingly small minority, probably despised (almost) as much by their "own group" (as far as people actually feel part of a group) as they are by you.

I believe it is the (incentives of) the (social)media and the bots that have made you believe otherwise, over time and in small steps.