I completely disagree. We don't allow those things because we know kids shouldn't be doing it. If there were no drinking age laws kids would still not be drinking and smoking weed because parents wouldn't allow it. That was kinda my point. (let's not talk about the outliers, obviously some kids smoke and drink)
https://www.niaaa.nih.gov/publications/brochures-and-fact-sh...
> If there were no drinking age laws kids would still not be drinking and smoking weed because parents wouldn't allow it.
In places with more relaxed drinking laws, we do often see more kids drinking. 42% of 15 year old boys were weekly drinkers in the UK in 2002.
https://www.euro.who.int/__data/assets/pdf_file/0007/382840/...
> Most young people begin using alcohol between the ages of 12 and 16, an age at which they gain increasing independence and spend more time outside the home unsupervised. At the same time, the direct influence of parents diminishes and friends become increasingly important.
But, alas, Instagram is not a regulated drug, and I see little reason why most parents' reactions wouldn't be more similar to those they have for video games or watching movies than it would be to the use of an illegal drug.
A more apt comparison might be a parent who doesn't let their kid go to the movies or play video games with their friends.