> just reuploading full youtube videos from channels like Kurzgesagt (...) it's also a sign of a successful platform
No, not really.
Ripping Youtube content is trivial, so you basically have a raidable pool of high-quality content that you can re-upload and monetise, that you didn't have to pay for in any way.
If you're seeing a lot of Kurzgesagt vidoes on TikTok, all that means is that someone found out their monetisation success rate for those stolen videos is high enough that it makes financial sense to carry on doing it.