>You'll find that the vast majority of people are vastly less extreme than what twitter and reddit would have you believe.
Yep. The medium itself makes everybody look about 100 times more radical than they actually are.
Look at it this way: if you're busy working on a small technical detail, your conversation will be around that detail, right? You may be an asshole, and it looks like he's working on that, but you're an asshole trying to make something useful. That is, you have a goal that you can be measured against. "I am not able to fix this problem because I cannot talk to people online without pissing them off" is a problem with delivering tech that you can identify and fix.
Sounds like your filter works for a while, as long as everybody agrees on some larger value structure.
Where all of this falls apart is when there's no larger structure that agreed upon. You see this in startups or academic/political discussions. Sometimes you know something's wrong, and you feel strongly about it -- but you're unable to articulate it in a manner that can be easily consumed. That's almost always going to come out wrong. But it needs to come out.
Contrast this with the rest of the internet, where people are not creating a small detail inside an agreed-upon value structure. There's no evaluation criteria except for bike-shedding. They've got nothing to do but to look at whatever your communication is in the abstract. There's no overall gain that might be weighed against bad phrasing. It's all downside. "I don't think that was a very nice thing to say" This can be both a true and non-productive thing to say in certain circumstances. That reality sucks, because people don't want to hear it -- after all, they don't share your value structure -- add to that plenty of time on their hands and an unlimited ability to look back on anything you've written. The system itself has problems.