This was an argument that was used to not ban smoking for kids in the UK back in the day. From the parliment debate...
> [banning smoking would] afford a direct encouragement to children to smoke. Most boys of a tender age who might be seen smoking in public places did so, not because of any attachment to tobacco, but because they considered it a practice in advance of their years, and something moreover which their elders told them not to do, affording them, therefore, the added pleasure of disobedience which was so dear to boys of their age.
I should have been more explicit, if I understand you. I support not just making it illegal for any minor to be on any big SM, but also creating standards and specifications for data ownership, controls, collection, and privacy that are hard and accompanied with extreme punishments, i.e., per intentional, negligent, or reckless violation; per data point, not incident. Make the companies aware that a single event can crater the whole corporation if the corporation cannot prove that its officers did not act in violation of the corporation and are therefore personally responsible, and they will keep the rules.
> [banning smoking would] afford a direct encouragement to children to smoke. Most boys of a tender age who might be seen smoking in public places did so, not because of any attachment to tobacco, but because they considered it a practice in advance of their years, and something moreover which their elders told them not to do, affording them, therefore, the added pleasure of disobedience which was so dear to boys of their age.
https://hansard.parliament.uk/commons/1908-10-13/debates/6aa...
Perhaps it does make it cooler - but undoubtedly the restrictions reduced availability and reduced the number of children being addicted.
As for the actual age cut-off, it's always going to be fairly arbitrary, or a 'balanced judgement'.