You clearly misunderstand the sheer scale of online advertising (compared to linear TV ads, magazine ads etc). There is no chance you can vet every single creative and a landing page (one public number is 30B daily ads just served by Google alone in 2012 - which is probably closer in spirit to the Punic Wars than to 2026).

That's the first point. Now, who should be responsible for getting the ads? The website? That will absolutely kill the monetization model and it is simply unrealistic. Which means, that responsibility now should be pinned on someone else. Who would that be? My point being that no one there has an inherent lawful obligation to provide such vetting, which would be a) costly and b) only applicable to one player (out of many).

And then we get to bad actors. If I were a really motivated bad actor as early as in 2005, I was serving different creatives and different landing pages to different audiences - a perfectly well-behaved ones to Google's crawlers (again, Google does A LOT to fight malware), a questionable quality clicky ones to general audiences and maybe malware-ridden ones to specifically targeted audiences. And you would not be able to catch me in real time - only after the fact, once the campaign was run and someone looked at the evidence (assuming it was collected, which it isn't normally)