I had a kind of social media when I was a teenager. It mostly involved dialing into a BBS or two, and its easy to think that it was harmless because it was a positive thing for me, but even I have to admit that there were dangers and even though those online places were similar they were also very different. Social media platforms are designed to be harmful in ways that a BBS just wasn't. There were no algorithms trained on data collected from multiple sources and focused on driving endless engagement. There were no people being paid to pretend to be regular users in order to secretly push products on me. There were games, including some that some parents would probably find objectionable, but they didn't constantly nag at me to buy things with real money (or virtual currency that could only be reasonably obtained with real money), and corporations didn't populate those games with brand ambassadors and ads.

It's too easy to look back and think "I survived online", but what adults today experienced online as kids is very different from what exists online for kids today. It's not just parents who are saying so. The social media platform's own research shows that it's harmful.