>am I the asshole" and idiotsincars are pretty normal places where people can politely disagree

These places are echo chambners too you just don't realize it because you agree with the echo.

Go on I am the asshole and give even the slightest hint of approval for a parent that's parenting in a traditional manner (e.g. approving of a "my house my rules" attitude toward an older teenager) and you'll get all sorts of hate.

Go on idiots in cars and talk about how people can't be expect widespread compliance for asinine road signage (like a 55mph speed limit on an interstate highway designed and marked for a much higher speed) and you'll be inundated with "hurr durr the law is the law" types.

There are visceral reactions (I’m pretty sure you can catch yourself doing the same from time to time as well), but my opinion/experience is that well-meaning and well-explained comments are well-received in most of the not-completely echo-chamber subreddits.

These examples seem overblown, and likely a false equivalence

Or instead of pontificating from your armchair, you could go check and see that it's actually pretty accurate.

"It's a useless echo chamber" is the number one complaint I see about aita.

I can check from my armchair, thanks. You get lots of different opinions, it's just that the hive mind forms an opinion around whatever the current topic du jour is. This opinion changes day to day, it's not a place where people have political agendas that are exacerbated by like minds. It's just people in large groups.