So this is a controversial topic with strong feelings on both sides. My position is that I hear a lot of young people (20s) look back on their teens and talk about the terrible impact social media had on their lives and particularly their mental health.
Obviously there are some positives about social media, but there is also a hell of a lot of negative: constant comparison, body image issues, social contagion of issues like eating disorders, political echo chambers, self-harm, images of porn, bullying, grooming etc etc etc.
Many parents I know don't like it, but feel that they can't really limit or stop SM because it would leave their kid socially isolated. Personally, it doesn't seem to me like that would be worse than the current situation, BUT if there was a grassroots movement of parents who said: no social media until a specific age (16?), that would solve the problem. If half the other kids at school weren't allowed it either, your kid wouldn't be left out. It's just you need a critical mass of parents to do it.
So: YABU = social media is on balance a force for good OR no-one would agree to this.
YANBU = sign me up!