Seems like a lot of banning. Why not just prosecute the ad network for conspiracy to commit wire fraud whenever a fraud case is tried that involved online advertising?

It’s one thing for a platform to not be responsible for free content, but entirely another to take money from a fraudulent enterprise and enable their fraud.

Edit: to be clear the reasonableness legal concept would be in play here in the US. Plenty of frauds could slip by a reasonable advertising network review. Some clearly would not.