However, Charlottesville, and their speakers should absolve any idea that this is a joke. These white supremacists actively call for violence against other, and then proceed to enact it.
The distinction here, is the "call to arms"->"illegal action directly related to call to arms". And I do believe that Cloudflare and others have a distinct responsibility in this.
Tl;Dr: say the shit you want, but once you bring violence into it, all bets are off.
In my opinion Cloudflare should not be in the business of making judgement calls one way or the other. The law exists for a reason and, as in this case, when a group is seen as acting outside the law, Cloudflare can be directed to terminate access. They need not preemptively act as judge, jury, and executioner themselves. Another issue is that when you start refusing to accept some group or another, it leads to an implicit endorsement of all the other groups. You can certainly find all sorts of completely abhorrent sites that utilize Cloudflare. A social campaign showing this sites while emphasizing that Cloudflare can, and does, refuse service to sites for what might be perceived as 'lesser crimes' would leave them in a difficult to handle situation. And this will happen. By contrast, not all that long ago they could have simply and eloquently responded, "We do not judge content."
[1] - https://en.wikipedia.org/wiki/2017_Congressional_baseball_sh...
[2] - https://en.wikipedia.org/wiki/2016_shooting_of_Dallas_police...
https://en.wikipedia.org/wiki/A_Modest_Proposal
Poe's law can become a cudgel when paired with takedown rules that companies don't want to (or can't) enforce with the level of thought as a real court decision. I don't like cloudflare saying that they're totally absolved of responsibility, but I do have a lot of sympathy towards their CEO's complaint about being the gatekeeper. If I was in their shoes, I wouldn't want to have to try and formulate a policy rule that keeps Solanas but bans whatever satire or allegory the alt-right publishes.