Google lets you turn off "personalized ads" if you don't want them. https://support.google.com/ads/answer/2662922?hl=en

That only lets you stop seeing the personalized ads. It doesn't say it stops tracking you.

What's wrong with them building a profile of me as long as I consented to it? Are you opposed to consenting agreements between willing adults and companies?

Well besides the creepy factor of what this data could be used for, the average user doesn't "consent" to it, because they have no idea it happens.

Then in this case the problem seems to be ignorance. Ignorant people will always find themselves in trouble though. Anyway, you still haven't proved that they wouldn't be ok with this even if aware of it. I've talked to many people about this and most were ok with it. I think you're assuming a lot here about what others care about.

It seems like you have a problem with people consenting to things you don't like, just like homophobes have problems with gays because they personally don't like consenting to same sex intercourse and think gays are ignorant of some facts (they're going to hell etc), maybe people don't care or believe in these facts and are just enjoying themselves, ever thought of that? What's the problems if other people enjoy things you don't? Live and let live.

Because, in 5 , 10, or 200 years. When societies (or rules) change, it will be used to discriminate or worse.

"Whoever doesn't study history is doomed to repeat it.'

Well, if we have people willing to kill us based on the type of socks we like or porn we enjoy, we have a bigger problem than the fact that this information is being collected. It's not like people willing to kill for such ridiculous reasons would be stopped by the lack of available data. Crazies don't really care about fact and data in general. I think you're assuming a bit too much about them.

Obligatory xkcd about it https://xkcd.com/792/