I'm not much of a libertarian, nor a free speech maximalist. I'm not sure I'm all that interested in that discussion either really tbh. I'm not sure what nostr people would argue along those lines of it being an iteration of free speech. I'm totally ok with paedo content being blocked.
I can see your point that political ideologies (both left and right) being potentially unwelcome, but there is the opportunity for people to make clients and host relays. I don't really know much about the infrastructure of Nostr tbh and I'm not going to pretend I do. I also don't see this happening any time soon, if it does happen at all.
The right wing fairly ok on twitter, and a lot of the left. Perhaps not happy, but at least not extremely disgruntled, or perhaps left and right are equally disgruntled but not budging from twitter lol. (And the libs have bluesky ¯\_(ツ)_/¯). So I don't really think it'll be something to worry about now/near future.