Back in the bad old days of adobe and flash plugins in Internet explorer, malicious ads targetting those were the malware infection vector in something like 80% of cases. Browsers have gotten better, but it remains the case that ad networks are the single easiest way to inject your mal-content into another website.

We see headlines about this-- about the Israeli firm that was abusing this, for instance, to hit targets-- and I am left scratching my head. Of course...?

IMHO it's the duty of any techie (with the social capital to influence digital hygiene) to ensure they and theirs are set up with at least ublock lite.