Earlier quoted context omitted.
Almost certainly they are using that for audience segmentation and ad targeting. Clever and disgusting. This isn't the invention of some evil moustache-twirling executive, this was the invention of an employee or group of employees who value money more than morals. We should think of such employees as henchmen.
if they do a better job at showing me an ad that might be relevant to me, how is that disgusting? if I have to see an ad at all I at least want them to give it their best shot
You'd say that's a ridiculous and illegal thing to do without you explicit consent, right?
Maybe you personally don't mind and would be happy to offer that consent. But they're doing it without your consent, regardless of whether you want it or not.