What? Why would parents need permission from their government to forbid their kid from having an Instagram account? They're parents, so they can engage in parenting.
Not allowing as in "giving them permission", but "allowing" as in enabling them to do so.
Right now if a parent says "You can't have instagram. Because I say so." the kids answer will be "But I will be a looser noob if I can't. All my friend are on it. Jenny has 5k followers!"
Vs after the ban: "You can't have instagram. This is the law." "But mom! Some of my friends are on it. Jenny has 1k followers!" "Is that so? I will ask Jenny's mom if she knows about that."
It is not going to stop absolutely everything. (Same as prohibiting underage alcohol drinking is not stopping teens from drinking any). But it will put a serious damper on it and fracture the social networks into smaller more underground ones.
What? Why would parents need permission from their government to forbid their kid from having an Instagram account? They're parents, so they can engage in parenting.