I think that'd be best, basically an entire porn federation completely isolated, we can name it horny jail!

They could, but it will only mean that you'll need separate account for porn, and most redditors do exactly this.

That's fair tbh, it may be wise to do that. Even if other instances still allow NSFW or suggestive content in general (such as art, medicine, gore, etc), explicit porn in particular has high legislative expectations.

Legislators don't even understand the internet - they're definitely not going to accept that beehaw.org or lemmy.ml loading ifuck.butts content isn't actually beehaw.org's responsibility if that's where the users are registered, where ifuck.butts content is frequently displayed.

I suspect that porn subs may end up federated with each other though, and it just means Lemmy users shouldn't be horny on main (ie have separate Lemmy acc for this fed and that one). Otherwise they'd struggle to be discoverable and would each require their own login.

(also, funny joke if somebody creates ifuck.butts so my comment becomes a discovery portal for them lol)