> The fundamental question that needs answering is: should we actually prevent minors below the age of X from accessing social media site Y?

This is only an interesting question if we can prevent it. We couldn't prevent minors from smoking, and that was in a world where you had to physically walk into a store to buy cigarettes. The internet is even more anonymous, remote-controlled, and wild-west. What makes us think we can actually effectively age gate the Internet, where even Nobody Knows You're A Dog (1993)[1].

1: https://en.wikipedia.org/wiki/On_the_Internet,_nobody_knows_...