I recently had a similar problem, browsing a reputable news site (newstatesman.com), I accidentally clicked an ad and got taken directly to a page containing explicit pornography. I complained to the site and they said they do what they can in terms of blacklisting ads, but they don't have enough time or staff. I can't believe there's no ad network that will take a stand against abusive advertising and actually vet t…
You would think some of the most profitable companies in the world could afford to hire a few interns to put eyes on any and all ads before they go out.
They do, all creatives are audited on submission. You can't provide literally ANY creative at bid time, it has to be one that's been audited. It's people that then switch the creative once the audit has been completed that are screwing everyone. It should result in you being banned from the network, but it's hard (apparently) to ban people that are paying the bills for you the ad network.