Well lets name them....
"...the advertising networks upon which they relied for dynamic content were inadvertently serving malware – which in turn, was not due to an explicit compromise of the networks; rather, it was due to the networks accepting ads from a malicious source without screening detection"
name the ad-slinger agencies. Then "customers" (if they don't already) can block them, people that pay for legit services can drop them and content filters (browser or software) can block them.
If say Amazon had hijacked pages that installed crap on a machine, we would soon know, so why are the ad-slingers getting away with it.