I liken the internet to press. Most of it sucks, but having it and being able to freely speak through it, is essential to liberty.
I mean, if we as a society don't believe people like this should have a free internet like everyone else, we deserve the closed internet we will get. Freedom sucks because you have to listen to a lot of assholes, but it's much better than the alternative.
This isn't censorship. As far as I know, no one has the "right" to an entry in the public DNS, nor is any registrar required to do business with Nazis. Registrars have the right to free association and speech too.
But besides that, my understanding is that though the internet is free, the various entities on the internet are equally free to refuse service. After all, if they were otherwise obligated, that would imply X's freedom can override Y's freedom, which also contradicts the nebulous ideal of freedom.
Even if it only serves to waste their time, hassling fascists is still a public service.
b) Use a Tor hidden service.
c) Petition the US government to force private businesses to serve their organization.
d) Start their own registrar with a ToS allowing such content.
Multiple options available.
But I wonder where on the internet unpopular speech will be hosted?
Even if the UN (and nations) declare internet a human right, where will content be hosted? Will the UN be able to force nations to change their laws to not persecute unpopular speech?