The fact that online advertisements are actually code that runs on my computer removes the moral qualms, for me. We live in a safe world now, but reading about how intelligence agencies, communist international, and the like operated between the end of WW1 and the cold war really drove home the fact that you do NOT want human beings building a dossier on you, and that fighting for privacy is not a matter of paranoia.
But you don't care enough to stop visiting the sites themselves? As if the "dossier" can't be built without ad code?
I can't think of any good reason to forcibly separate a website from its ads. Any arguments against the ads are just arguments against the website, and I think attempts to argue otherwise are just trying to have your ad-free cake and eat it too.
Somebody paid and is paying for your visit. For the website itself. It's somebody's labor. If they didn't want ads, they wouldn't have put them there. Clearly you've gone to some length to convince yourself that you're justified in your actions, but you're not. You're taking something for free that the creator intended to be paid for.