CF terminating their service absolutely does not silence them. They have many other ways to get their message out, even ways that look identical to what CF was providing.
If they end up actually getting turned away everywhere, and have no avenue to get their message out, then perhaps that's saying something about what everyone else things of the quality of their message.
And yes, this sort of thing needs to be decided on a case-by-case basis. If every internet company decided to disallow accounts held by people of a particular ethnic group, then that would be a problem. But I don't see an issue with every internet company deciding they don't want to participate in spreading hate speech and giving a hate group a platform to spread their propaganda. We wouldn't be arguing about this if we were talking about shutting down a website distributing ISIS recruitment videos, would we?
For what it's worth, yes, I would still argue that ISIS recruitment videos should be allowed on the internet. (But I could see my future self renouncing this as immature and un-nuanced.) Because in general, I am more afraid of overreaction to terrorism than terrorism itself.
That's true that there are alternatives to CF. As long as there is at least one anti-DDoS provider with an "everyone is welcome" attitude, I suppose CF can do whatever they want. So I'll concede that point.
If they end up actually getting turned away everywhere, and have no avenue to get their message out, then perhaps that's saying something about what everyone else things of the quality of their message.
And yes, this sort of thing needs to be decided on a case-by-case basis. If every internet company decided to disallow accounts held by people of a particular ethnic group, then that would be a problem. But I don't see an issue with every internet company deciding they don't want to participate in spreading hate speech and giving a hate group a platform to spread their propaganda. We wouldn't be arguing about this if we were talking about shutting down a website distributing ISIS recruitment videos, would we?