1. Much of the moral relevance of the usage of any substance is dependant upon WHY it is used. If someone uses it everyday to escape reality or to simply feel good, to the point that they are doing nothing productive with their lives, that is obviously a problem. Someone using it for pain and the like, is completely different (although there are better things for pain). No one (except those whom are rightly ill) should ever be dependant on a substance of any kind to make them feel better or to help them get through life, that is the definition of addiction. Aren't there better, more productive things, one could do with one's time?
2. Mind altering substances like drugs and alcohol are just that: MIND ALTERING. If someone is in an altered state of mind they are not in a position to make good decisions. Indeed, I'm sure most of us know of someone whom has "gotten drunk" and "made a mistake."
3. Alcohol IS legal and I still don't think it is ok for people to abuse it or binge drink. My father is an alcoholic, so I'm quite aware of the moral issues involved with all substance abuse problems. A glass of wine with dinner and such every now and then is fine. Getting so drunk you don't know whats going on and you are hurling out half of your intestines only makes you look like an idiot and you could make VERY bad choices under the influence of any substance! Getting so stoned that you don't even know whats going on (and could again, make bad decisions) only makes you look like an idiot and is a waste of your life/God given time.