You may disagree on this, but many people believe that the current state of affairs wrt online ads (i.e. massive privacy violations and using ads to get people literally addicted) in general is the inevitable end result of any predominantly ad-supported ecosystem.

Commercial unrequested ads in general, they are designed to manipulate you to make you buy products you wouldn't have bought otherwise.

Additionally, a related negative side effect is consumerism.

Would you tolerate a human being following you around, telling you to buy things you don't need and that you are worth less if you don't. That's what ads do, except it's not just one person but a whole team of professional psychologists that know just what buttons to push to make you cave in. Pretending that they are simply businesses informing you is beyond dishonest.