Part of my job requires me to counsel substance abusers. After reading this thread over, The vast majority of posts in this thread seem to rationalize and justify why it's ok to abuse alcohol.
depends if they are abusing it. for me, I'll have a few drinks a few nights a week - usually friday and saturday jamming or playing or if we have company over to the house. Am fully aware that the metabolization of alcohol produces a by-product that ends up destroying brain cells and liver cells and probably any other cell in your body. Am also aware that I don't like the feeling of being drunk, so usually stop after around 2 or 3 drinks (unless you're at a party, then the tendency is not to notice it as much because of the way alcohol effects your consciousness - and we are all social animals). They key is, I often go without, and don't miss it at all when I do. I might often want a drink during a night, but don't go out of my way to get one.
The thing about this topic that interests me is that it is an interesting study in human addiction, anecdotal may it though be

Human beings are addictive by nature, that is how we survived so long. Something was good, so our brains tell us more. And we are quite single-minded and vigilant about getting it. This is good for things like filling hunger pangs, thirst pangs (mind you, food is a drug too, so not surprising), and sex (without which our species would have died off long ago), shelter, Maslov's heirarchy, you get the picture... All tied to instinct no doubt in an integral way. Anyways, a by-product of this is that we can easily get addicted to anything that gives us pleasure. So we are all addicts, and all have the potential to be addicts, without question. The only thing that prevents anyone from being an addict is either social conditioning (some would put religion in this category) or self conditioning (putting up with less pleasure now in order to gain more later - the ends justify the means... ie. you don't drink yourself into the ground because you have a family, a job, have a goal in life, don't want to just eat chocolate and masterbate all day while getting high, etc).
But drinking and generally obscuring consciousness in any way that is even slightly pleasurable is a natural part of the way we are made up. I prefer self-conditioning myself

although can empathise with those that need some social conditioning as well.
cheers,
meta