I think the biggest problem with it is that it is deeply flawed and the writers were afraid to address the real problem. There have always been dangerous boys. They existed long before the invention of social media and the smartphone.
Men have been killing 2-3 women a week for decades and that number has remained stable throughout. It hasn't suddenly spiked with the introduction of the smartphone. Adolescence couldn't explain anything and offered no solutions, compared to something like Curfew.
The show hinted at intergenerational violence but was afraid to really go there.
The female characters were entirely male gaze and given no room for depth at all. Katie as a victim was entirely ignored. And they also managed to throw in girls are as bad, by having a girl assault a male pupil while everyone just stood around and watched, including the adults.
It was suggested that Jamie was spending all his time online and alone, and yet he was out for hours until late at night with his friends, so not online and alone at all. It was suggested that he was decent and normal and no-one had a clue, which doesn't ring true with what is known about boys who have done this IRL, where they've had contact with multiple agencies in the months prior. It was suggested that he was a lone wolf, but his friend gave him the knife, and that wasn't explored at all either.
Almost all boys are online now, and almost all of them don't go on to kill anyone. It's incredibly rare.
Thorne has fixated on the idea that it's all about the phone when it's not, presumably because it seems to offer a solution that makes parents feel better. It's obvious that social media and the way algorithms work is having an effect on boys with a certain disposition, but they have to be that way inclined in the first place. It encourages them but it doesn't create them from scratch.