If they don't track you they have no way to serve you relevant ads, and I would much rather want relevant ads than ads which promote useless products to me.
They don't want to show me ads for things I'm already interested in, they want to make me interested in things I didn't know about, or more interested in things I knew about but wasn't going to buy.
They don't care about relevant, they want successfully manipulative ads.
It is extremely rare that I ever see an ad that is actually relevant to me, with tracking or not. When I do see ads that are relevant to me they are completely useless (ex: showing me the exact product that I just looked at a few minutes ago and nothing new). Furthermore, I have been conditioned to completely ignore anything that might even look like an ad. I can't think of anytime that I have ever bought something because I saw an internet ad for it. I have purchased things that were recommended and/or reviewed by a trusted source online. Context and qualifications are much more convincing and influential than a box telling me to buy something.
I think it's very easy for different people to mean different things when having conversations on this topic, so it's good to spell it all out.
They sell this data(even if it's anonymized).