No fundamental difference between censorship for being an anarchist humanitarian and for sharing CSAM. There’s a hierarchy, the top of which either decides to ban you or press someone else to ban you.

If the hierarchy is voluntary (as in paying attention to deletion\ignore messages signed only by those authorities you chose yourself), then both CSAM and anarchist speech will be shared.

Best you can do without enabling censorship is to choose what you replicate (Freenet doesn’t have that, hence CSAM flourishes there, with this thing it might be less convenient - you’ll have IP addresses of all the pedos ; sharing CSAM is a crime so it hurts them, being an anarchist is not so it hurts anarchists less ; though some way to achieve pseudonymity with still only storing what you want would be good).

Not with that attitude.

As long as they are able to create their own subplebbit , otherwise every subplebbit (by the description) has as moderator the owner (or someone given the permission).