When I forget to sign in to YouTube, I see the same pattern, shitty ads that are clearly only allowed because otherwise YouTube wouldn't have sufficient ad inventory to meet their internal KPIs.
For example:
- gambling, e.g. slot machines, sports betting
- healing crystals
- palm readings
- carnival games
Perhaps the right distinction is whether something is legally a fraud or not. But I kind of agree that most ads are scams and also that ad networks don't have the ability to separate legal scams from fraud. So I just block them all.