The truth is there isnt a line, maybe alcohol and smoking shouldnt be legal, if we knew what we know now back when smoking was becoming popular i am sure it would have been outlawed.
Drinking is basically a part of being human ,we have been drinking for thousands of years and its an accepted social lubricant. Sure binge drinking has health consequences, not to mention can make you take risks, but what it comes down to is drinking in itself isnt dangerous, drinking too much, like anything done too much is dangerous.
I am sick of people as a line of reasoning saying pot should be legalised because "omgz look at alcohol its so bad" thats not a reason for legalisation, its a reason for why alcohol should be restricted and policed more. Not to mention the fact that almost everyone drinks and its legal, so numbers cant easily be compared with pot which is illegal. No one has ever died from smoking pot? bullshit, plenty of people have had car accidents and THC has been found in their blood.
Alcohol and drugs lead down the same path in my opinion, just with alcohol its a slower process.