Basically, the good parts of free speech arguments.

I do think there are things that can just be banned from existence, and be made illegal, but it's significantly more tolerant than the current vibe.

Reality doesn't give a shit about our systems of morals. There is a certain "mainstream, harmony and political correctness" creep that sometimes happens. And what's bad about that, is that bubbles brain wash themselves into believing that the way they think the world works is really how the world works. And what they hold isn't just a perspective and an opinion, but a fundamental truth about the world and deviation needs to be purged. And that eventually collides with reality. This is both true for racists and for people who think racism can be "cured" or "educated away" or "people can just consider the facts and change their mind".

The fediverse allows a more gradual interaction than centralized social media sites. Because centralized social media must decide how to deal with... depiction of politics, religious subjects, NSFW topics, which btw, covers everything from violence over nudity to medical conditions.

If there was a medical community sharing discussions about medical topics, I can block that and be unburdened by it, but there is no central fediverse authority that needs to decide if that medical picture is not allowed because there is a boob in it.

In short, banning a social group on social media, like racists, doesn't convince anyone or remove that group of people from factually existing and factually organizing.

Open Source Software works the same way, you can't be sure that math library isn't being used to control a remove controlled ballistic missile, but pretending that you can "ban math" depending on the purpose is stupid, so there is no point in worrying about it.