So "the network" in context of sites like Facebook or YouTube is a fancy marketing term for "the website." Peertube servers actually federate, so there is actually a network there.

You don't have to federate. As host, you can host whatever you want (you are of course subject to laws in the country you're hosting in) and censor whatever you want on your server. You can basically do anything you want.

If you host adult content like pornography it is very likely the larger federation will not federate with your server, and for adult content that isn't pornographic in nature it is probably best to require content warnings.