The social media ban is similar to the logic behind gaming limits in China. The idea is that while the controls themselves are easily circumvented, it gives everyone an excuse to do the right thing.
Parents don't have infinite "control tokens". I only have time & energy to put my foot down about a limited number of things. It is much easier to establish conventions around responsible behaviour if the whole community is behind it.
I am OK with this ban for the same reason I'm OK with tobacco sellers being not allowed to sell to under 18s.