Ultimately it's very difficult to separate "that's a bad opinion, downvote", from "troll, downvote". People won't even agree on which is which, especially the trolls.
If you require someone to post really blatant stuff like "Hitler did nothing wrong" to be ejected from the discussion, then your discussion will be filled with ideological trolls who don't argue in good faith but insist that any moderation to their participation is censorship and echo chamber creation.
Their theory that Global Warming is a big conspiracy demands attention, and they have plenty of links to "studies" to back it up.
If you require someone to post really blatant stuff like "Hitler did nothing wrong" to be ejected from the discussion, then your discussion will be filled with ideological trolls who don't argue in good faith but insist that any moderation to their participation is censorship and echo chamber creation.
Their theory that Global Warming is a big conspiracy demands attention, and they have plenty of links to "studies" to back it up.