Rather, the observation is that these things happen mostly outside of school, so avoiding schools isn't an effective way of avoiding this things.

The link between school and these activities is, IMO, largely specious. Or at the very least completely unsubstantiated by evidence.

Or are you seriously suggesting that kids are binge drinking and lighting up in between history and chemistry?

Basically, vivek's argument is that by not sending your kids to school you avoid all of these behaviors. But these behaviors are far more common outside of school that within school.

Home schooling doesn't replace effective parenting, and sending your kdis to a school doesn't preclude effective parenting.

Finally, I think it's worth asking so what?! to a lot of your statistics. Particularly the "drank some alcohol" and "smoked pot in the last 30 days" statistics. These things aren't a priori bad, and drinking at that age isn't even illegal in a lot of developed countries (and even in some places in the US, under adult supervision).

Kids are smart. Claims that "marijuana and drinking are bad" tend to only have the effect of discrediting the speaker. Those claims are mostly specious, and kids know how to use Google. Citing something like "68% of 12th graders have tried alcohol" in a page decrying substance abuse makes one look like a scare mongering idiot. Seriously, these are 18 year olds -- that number is almost certainly close to 100% in a lot of developed countries.

But kids are also stupid. If you go on to tell them "binge drinking is bad, avoid it" or "prolonged marijuana use really can cause serious harm", they'll extrapolate that you're BSing them about that too.

Basically, scare mongering about any drug use only has the effect of making it far harder to warn kids about actual dangers.