These are the same busybody nanny-staters who tell us that it is "illegal" for our kids to drink, drive cars, buy guns, or share pornographic pictures of themselves.
But seriously - if you think social media is harmful to children, I don't see why you would oppose making it illegal. It would be illegal, neglect, for example, to let your children wander into a busy street. Why should it be legal to let your children come to harm in other ways?
I'm not actually sure that social media is harmful, or how harmful, or what qualifies as social media or as "use" - but if we grant that it is harmful, it should be illegal. Doing otherwise just adds another advantage to children with good parents. Making it illegal will, hopefully, reduce the amount of harm done to those who do not have the maturity to decide things for themselves.
I'm not sure it ought be "neglectful" or "illegal" to let kids wander in a busy street. Every day I see a huge swarm of kids, including 5th and 6th graders in elementary school, walk home without parents from school. That includes crossing intersections and commercial venues. I don't think that as neglectful activity.
In Japan there's a popular TV show where kids (max age 6-7) wander around their town to do shopping chores. Despite the fact that this is a TV show and thus there are going to be employees secretly posted around with cameras, it still displays a cultural sensibility on when children should begin to be trained to be independent.
Now, should kindergarteners cross a very busy street alone? Probably not. But in the city I'm talking about each family makes their own choices and the sum of all this is one of the safest places in the world. Police cars do not regularly patrol around and the community is very, very prosperous and optimistic.
Meanwhile we have a recent story of a mom who got charged for child endangerment and convicted and sentenced because she let her kids walk alone.
You're missing an important distinction that I may not have made clear: a lot of activities that can be harmful to children can also be valuable. There's a lot of harmless fun on television, walking alone to the park or a neighbor's house fosters a healthy sense of independence, weight training done safely can help build strength and confidence and sugary caffeinated sodas in moderation are… tasty? (Not sure about the benefit on that last one.)
Like these activities, social media can have their benefits even for young people: contact with friends and family far away, connection with others with similar interests, and a broader view of the world, among others. With guidance, kids can experience those benefits without too much of the harm.
In most of the cases you point out — drinking, driving, buying firearms, and sharing pornographic pictures of themselves — any good there may be is vastly outweighed by the dangers. I don't believe the harm so disproportionate with social media, but I suppose others might disagree.
But seriously - if you think social media is harmful to children, I don't see why you would oppose making it illegal. It would be illegal, neglect, for example, to let your children wander into a busy street. Why should it be legal to let your children come to harm in other ways?
I'm not actually sure that social media is harmful, or how harmful, or what qualifies as social media or as "use" - but if we grant that it is harmful, it should be illegal. Doing otherwise just adds another advantage to children with good parents. Making it illegal will, hopefully, reduce the amount of harm done to those who do not have the maturity to decide things for themselves.