The negative effects of social medias as they are today is plenty documented.
It is harmful for literally everyone. But big tech made it so that they integrated themselves in pretty much everything.
Lots of organizations use Facebook groups to vehiculate important information, that won't be elsewhere.
This bullshit law is lazy and a way to bullshit people when politicians are pressed about what they are doing to curb social medias created societal issues.
Yes, parents are responsible for what their kids are watching, but it is extremely hard to avoid social medias because they were closely integrated into our everyday life.