Because binge drinking, even acutely is rather dangerous. The harms stemming from acute pancreatitis, renal failure, fatal respiratory depression, arrhythmia/sudden cardiac death (yes, booze can easily induce this even in healthy individuals absent of risk factors), permanent cognitive stunting (I believe given this data present regarding even occasional binge drinking that the majority of the adult populace has acquired some level of ethanol induced cognitive stunting due to teenage binge drinking)… the consequences of binge drinking rack up over the years, particularly regarding a drastic elevation in cardiac risk
I know quite a few kids who have ended up in hospital from binge drinking (one who was in a coma for about a week after falling and breaking the back of his head open on a rock)… I know one who died from choking on his own vomit… I’ve had to take someone to the ER, consistently hold him up while unresponsive as he was choking on his vomit… he then threw up on me (terrible night, I didn’t have a single drink on this particular occasion, I rarely drink but I smoke pot probably 2x monthly, I’m cutting down the frequency though…)
People tend to make very risky decisions when drunk to boot… the amount of fights, stupid decisions/risky sexual encounters (like deciding to drive home after drinking fifteen beers), injuries due to impaired coordination/passing out etc I’ve seen due to booze far surpass what I’ve seen happen with cannabis… sure, a very select few react badly, the risk (one in a million) for cannabinoid hyperemesis syndrome does exist… but in terms of overall harm induced… I think most would think cannabis is safer.
These consequences aren’t something I’ve seen with cannabis, thus if kids are going to do SOMETHING in college I’d rather it be passing joints around a campfire, falling over laughing at their own terrible jokes and “high thoughts” than slamming down bottles of vodka, drunkenly hitting on one another, getting into fights and damaging property
Granted I’m well aware hard drugs are also present at college and high school, I’ve even tried a few things besides cannabis… but to me a reduction in teen (and adult) drinking rates is a win
Booze is also quite addictive in the grand scheme of things… the main reason I seldom drink is because I tend to have a problem controlling myself once I start… I’ve only ever had this problem with alcohol, nothing else, it’s just so good at numbing emotional pain… a few drinks for me can send me off on a bender (my alcohol tolerance is extremely high, not because I drink frequently but because… genetics.)… thus I abstain from drinking aside from on very special occasions, as once I start I just want more… and more and more