This seems to me like one of those spots where one's approach to ethics can play a big part in the conclusions you draw.
From a sort of Kant-style, deontological perspective, where you have to be able to say with confidence that something is morally wrong in order to make much of a judgment at all about it, yeah, it seems hard to mount a strong case against ads.
From a more Bentham-style utilitarian approach, it's easier: Are ads and tracking a net benefit or detriment to people in general? AFAICT, the only people who try to mount a case that the answer is yes are people whose livelihoods depend on everyone being OK with ads.
Then there's the "do unto others" approach you get from virtue ethics. The GP's take of, "I'm not going to monetize with ads because ads annoy me" reminds me of that.
It's interesting, because, if you could paint those three approaches to ethics with a broad brush, the latter two would be, "Let's try and make things as nice for everyone as possible," while the first would be more like, "As long as it's not actually evil, ¯\_(ツ)_/¯"