It's a good question. If someone comes on my forum and posts "I strongly believe that all Jews should be immediately gassed" am I allowed to ban him or am I obligated to provide equal service?
I think this comes down to whether you're a platform or a publisher, if you're a provider you're not responsible for what your usera do with your service, if you only allow selective use then you're implicitly endorsing whatever the users you allow do.
