A big part of going through teenage years is the development of one's own personality and finding YOUR OWN identity. Figuring out who you are and who you want to be, building real relationships with real people to learn about social contracts, trust, bonds, friendships, mistakes, and most importantly it is a key part of building a healthy amount of confidence and self-love which are important character traits that everyone should establish to some level in order to weather through tough times in life later on.
Social media makes all of the above impossible. Even worse, it makes this important development phase very toxic. It teaches teenagers and children the opposite of friendships, the algorithm is constantly looking to outrage children and to rattle their feelings in order to drive engagement. The algorithm is tuned to feed into young people's insecurities in order to drive clicks on ads and increase their ad revenue. This is why so many kids suffer from mental health issues, are immensely under confident, unhappy, feel alone and worthless.
It's shameful that policy makers are not acting fast enough. There is already a huge generation of damaged children who just turned or are turning into adults now and we already see the effects of that.