I don't think of it as 'cool' - I just view it the same as a preference.
Alcohol, weed, shrooms, and even some party drugs like ecstasy and such, are all fine in my book as long as they're done responsibly.
I think once you venture down the path of abuse, it's a problem. That goes for everything in this world - moderation is key.
Heroin, meth, and all the other hard drugs are a problem because they are so incredibly addicting that it's almost impossible for someone to use in moderation.
People have families that also need to eat.