Because your mega advertisers (Coca Cola, Disney, et al) are being played next to scam ads.

Also I think this should be a two way street. If content creators need to moderate their content lest they be slapped to death by Youtube to help the advertisers, advertisers also have a responsibility to ensure their advertisements do not cause issue for content creators and/or viewers.

It's unclear who currently runs Youtube, but they have been making bad decision after bad decision. Youtube is now extremely hostile which goes against the values it once held when it first grew.