On your third point, I want to reiterate something I've said before: Nazi's aren't stupid. They take advantage of people who want unrestricuted free speech without consequences and use it as a recruiting tool to radicalize more nazis. (https://news.ycombinator.com/item?id=23722215)

Kicking them off of a site raises the threshold for someone to be exposed to radicalizing factors. We have evidence that this is actually, really, effective at reducing rates of radicalization.