It's not only that. Books are not ads. There can be bad books filled with stupid ideas and garbage stories but the purpose of literature is not to advertise something.

Modern social media is just advertisement in disguise of entertainment. I am an adult, hopefully a rational one, and my buying habits (and desires!) have been heavily influenced by the social media, I can only imagine what it does to children's minds.

The social aspect of social media, ironically, is often barely present. Services like Youtube are parasocial at best.