The issue becomes with the internet being able to silence all dissent and create re-enforcing echo chmabers. The forces at play are not stupid and they target disenfranchised, lonely, young males full of angst.
Imagine a packed hall with hundreds of people loudly cheering for someone calling for genocide of X group, this is what these hate clusters look like and if we saw it in the real world no one would say "This is an acceptable cost of free speech"
There exists speech that has no redeeming qualities and serves only to incite violence and hate. To argue as many commented here have that outlawing this would lead down a slippery slope of authoritarian government censorship is simply ridiculous. We've outlawed child pornography and that hasn't led us down any slippery slopes.