It’s a form of “justice porn”. You’re right that these scammers are victims themselves. But seeing how they treat vulnerable groups (particularly less tech savvy, trusting, older people - which may well be your mom one day) is absolutely fucking vile.

Also, some anti-scammer YouTubers are legitimately very skilled and entertaining to watch. Kitboga is the first that comes to mind. He has all these voices, characters, sound effects - and takes scammers on quite some adventures. Pretty funny.