To hold this view you have to think of information as "not real", not like "real" molecules and receptors, the mind as distinct from the body, and then restrict the legal definition of harm to only "real" things.

This is an odd thing to do, because :

- information is real, it exists in the universe.

- the harm of social media is real, as measured by many of the same measures as the harm of smoking

Why not do something about ads? No, that's a good thought, we should do that too.

I think a decent conceptualization here is "psychic damage", as in a video game. These things deal a lot of it.