There was a time you could let a teenager use the internet unsupervised as long as they understood some basic safety. That time has passed. The only people to blame now are the parents.
That's a false dichotomy. I can blame myself for not keeping my family away from toxic algorithms, but I can also blame the facebook leadership for creating that monster. one that also infects every site I visit with trackers, and then uses that to push ads across my whole family.