I think that the way we educate children in schools could easily be described as prisons, where we subject them to artificially exaggerated social stresses because they interact with too few adults and do so in abnormal circumstances. We artificially induce extended childhoods, and delay the onset of mature adulthood. This not only causes absurd stresses but creates alienation from the nuclear family that would normally provide the adaptive environment that creates the calm, confident and healthy mind. So, we create alienation as a systemic condition in society. (Childhood as we understand it is a recent invention. And probably a bad one.)
I think that social media provides a form of competition against this destructive environment, that reduces alienation. And that the internet in general, provides so much information, that it is possible for children to find membership in groups regardless of locale.
So I think the argument is that school is the problem of alienation and we see social media providing a solution to alienation, and that some of us would prefer that such alienation did not need to be mollified by social media, and instead a healthy individual was developed inside of the nuclear family. But the problem here is not social media. It is education and the incentive for two parent incomes that make possible our intergenerational redistribution.
So, the net is, that social media, and the interenet in general, are net goods. The problem is everything else.