Still, Free Speech is important to some of us, You don't have my vote.
Free speech is important to me as well. That doesn't change the fact that speech here on this private platform is under the purview of the owner. If the owner were to take action - No one is being denied anything owed to them. We do not have a right to speech here without the owners approval. Valuing free speech means, at a minimum, understanding what it is. So, let's not get bogged down in bogus discussions about how rights (that don't exist) are being potentially denied.
Consistent and extreme voices can cause harm to a site. Is that happening here? Well, I agree with OP, DART compares negatively to the site it emulates. I think there is an argument to be made that some users intentionally rely on heavy rhetoric, propaganda, lies, dishonest tactics, etc. all having the effect of killing an honest exchange and comparison of ideas and ideologies.