Bad ads appear with every ad network, and ad networks are lazy to stop it because they know that sites will take all the blame (your comment is a great example)

Bad ads appear with every ad network, and ad networks are lazy to stop it because they know that sites will take all the blame (your comment is a great example). Pop into /r/adops sometime (or the associated slack channel) and watch site owners working nonstop to try to find a solution to this problem. It's mostly a game of whack-a-mole at this point with no real long-term solution in sight.