Earlier quoted context omitted.
The better thing would be to hold Google directly accountable for every malicious ad they allow through their network. If they cannot do that, they should not be in business selling ads then. Yes, that means amending the law (in the US). But the law as it is written facilitates crime.
How do you figure out what is a malicious ad? That seems really difficult at scale.
That's not required. Google could employ proportionality as many people reviewing what they advertise as, say, National Geographic Magazine.