It's definitely possible. First because the list of videos you advertise on an instance/channel is dynamic, not an append-only log like on a blockchain. So you

It's definitely possible. First because the list of videos you advertise on an instance/channel is dynamic, not an append-only log like on a blockchain. So you can properly delist a video from your Peertube channel and it will no longer appear to clients. Second, because even if people still has the infohash somehow and continue to seed it, there needs to be a mechanism to find other peers when someone wants to download the content (how did they obtain the infohash?). It's technically possible (although becoming harder with peertube moving from Webtorrent to WebRTC+HLS) but not a supported use-case (you'd have to write another piece of software for that). All in all, the situation is pretty similar to that of Youtube. Yes someone could have a copy of your cringy videos and decide to upload them elsewhere, but your followers would not automagically discover them. The same goes with Peertube, which is more federated than P2P in its design.