I think this phenomenon has also a lot to do with self marketing of ad agencies. To stand out against the numerous competitors, they want to provide as much information as possible to their clients about potential customers, target groups, etc.
I agree that we should block those even harder. The bad side is that whitelisting sites doesn't work well and well behaved actors are punished too. Especially those, since they do not employ measures against blocking in the first place. That does cost those sites that you actually do want to support.
So the current situation is that bad actors ruin it for everyone.