If you’re not port-forwarding, only peers that are port-forwarding can download from you. And you can only download from peers that are port-forwarding. There can be times where a torrent only has a few seeders, but they are not port-forwarding, and if you’re not either, you won’t be able to download the torrent.
Yeah, those were the problematic cases they highlighted. Image/video generation usually involves generating many permutations, perhaps adjusting prompts, and just keeping/editing the parts they want. The Trump video is likely made up of many edited clips from many different prompts, after discarding many more, not just one prompt. The song may be one prompt; haven’t played around with music generation myself.