Immune, no, insanely hard to police? Hell yeah. The thing with these laws is that it’s pretty easy for MS to sue Reddit and force them to comply. They have one centralized location to complain to. You can’t just call John Lemmy and have him comply. Would it be impossible for a state government to contact every single instance owner? maybe? But they’re not going to do it. Even if they made an attempt the instances hosted in other countries couldn’t give less shits about some southern US state.

Nostr is a whole other beast… it’s currently littered with things illegal in just about every country on the planet but that shit’s still there so I can’t imagine MS could do anything there either.

TLDR: Immune, no. Neigh impossible to enforce, yes.