Yes. Cases of privacy breach:

https://www.forbes.com/sites/kashmirhill/2012/02/16/how-targ...

And I'd argue that any time anyone bought something they weren't interested in before seeing an ad for it, they were harmed.

1 case 9 years ago is it?

You're assuming that a) buying things is bad, and b) you're interested in everything that's good for you and already know every product that exists.

It's obviously an example. You asked if anyone's ever been harmed - yes they have.

Chances are that the site you are on has some topic that could be the subject of relevant ads. That's how advertising has worked before it became a game of stalking every user to the maximum extent possible.

Yes, during chemo my mother bought on several reiki or hsimilar crooked pseudoscientific stuff to help her cope.

I'm not against seeing your occasionnal pastor/homeopath or other not-doctor that will at least take time to listen to you and rescribe placebo ater you unloaded on them (i think a shrink is more usefull and cheaper, but really i'm not in a crusade or anything, and i'm okay with sect/religion/"natural remedies" as long as it is not lithotherapy and you still get your chemo).

However pseudoscience stuff with no human component and just money is just taking advantage of fragile, suffering people. Aiming at them is as amoral as it get.

Tracking is shit because the ad industry is shit.