One thing everybody is forgetting is that drinking is a lot cheaper form of entertainment than just about anything else out there. I'm not even going to comment on whether American attitudes towards drinking are any better or worse than European, Asian, Arab, or otherwise...in college I was pretty broke, and splitting a case of beer with friends ($5) was cheaper even than seeing a movie ($9) -- and kept me entertained all night.
I think that helps explains why Americans don't drink like Europeans. (Of course, GFLPraxis, you're right that the asinine laws have a lot to do with it as well.)
My biggest peeve about drinking is those who talk about it too much. Either they're bragging about how they never drink because they're too good for it, or they're bragging how much and how often they drink to sell themselves as cooler than they actually are. Both are obnoxious. Just do what you enjoy as long as you're not harming others or yourself -- and I also suggest experimenting at least a little. If you're not going to drink, at least know why you're not doing it.