They don’t have to be legal. In Finland we are getting YouTube ads for a sports betting website. That’s illegal. (Only the nationally regulated gambling monopoly can do that, and even they have massive restrictions on what kind of advertising they can run.)

In the off chance that you can report the ad to YouTube (can’t do that on TV or Android), YouTube has nuked the ad. Doesn’t matter. The ad has been submitted via bazillion different advertiser accounts.