In the same way parents can be blamed for not keeping their children safe around guns/alcohol/drugs, they should also be blamed for not keeping the children out of digital dangers, and keep mandatory age verifications out of here.
Have these parents tried to not let the salesman in?
The "just say no" argument, basically.
There is also the education part that for some reason we are ignoring. Kids are going to be able to access drugs in locations where they are unsupervised, they are going to be subject to peer pressure, etc. The job of the parents is to prepare them for that, as they should prepare them for the negative effects of social media.