An echo chamber where the barriers are "don't advocate for bigotry" and "don't be a bigot"? Damn. Mighty big echo chamber ya got here. You can fit all sorts of amicable disagreements in here. Hell, you can even fit nearly uncivil ones too! Boy howdy there sure is a lot of space to disagree when the limits are this far out.
That's great if you can trust the moderation/censorship team to use a rational definition of bigotry. But what usually happens is they begin to enforce the standards of an ever-closing Overton window, to the point that mere disagreement with the hive mind is considered bigotry.
The limits of discourse never stay "this far out". Moderation distills this enforced consensus into a weird, unhinged fanaticism, one "deviant" at a time.
Centrist policies aren't the issue. It's the apologists for intolerant bigots that paint themselves centrists. All apologists for bigots are bad, and almost all of them paint themselves centrist. But not all centrists are bigot apologists.