If they ran less hostile ads, people wouldn't be as hostile to watching their ads. Some of the ads they run are just ridiculous and awful. Ads for scams, soft-core porn ads, just the worst of the worst.
Even google can't keep malware ads out of their system. If we say have geek squad remove the malware, its $149.99, all because google wanted to show me a $0.0001 value ad. No thanks.