Those sites exist specifically because all the popular ones specifically are designed to be echochambers, and boot the "controvercial" users off. So those users collectively move to other sites and start their own echochamber. And then when new people join, they arent seeing both sides of the conversation, which is a clear path to radicallization.

The way to fix this isnt with silencing, its by exact opposite -promoting controvercy and rewarding discussion around it while punishing low effort posts and replies.