[robotpepi]

It is true that people are not forced to buy things. But even if one is not _forced_ into something, one can be _manipulated_ into something. This is what happens with ads: they're most of the time misleading (and in many cases they lie, tobacco industry being the classic example), they encourage addictive or compulsive behaviors, they try to manipulate you emotionally (which is easier if they know a lot about you), etc. Ads have too much power nowadays so that they even shape reality, they're not purely descriptive as you say, that's way too naive.

And ML models are not only based on what you've already bought. On instragram, for instance, I have ads for bird toys/vets/etc because I follow bird owners.