Sure, but the vast majority of Peertube videos are under open licenses like Creative Commons, and I’m pretty sure you need to agree to having your video be torrented in the Peertube TOS when you upload. Basically, most videos made for Peertube is specifically meant by the creator to be shared in this way.

Of course, this wouldn’t apply to if someone uploaded a pirated movie or show, but seeing how regular torrents for those are everywhere, I doubt they’re having much luck taking them down. Think at best they’d be able to DMCA the home Peertube instance and get the main copy and listing taken down.