I do drink, but only in housegames with friends, where the point is to have fun, and not make money. But when I play online, I want to make money and I think drinking distracts me, or I can't keep concentrated. This is why I don't drink.
I don't think its right or wrong, it depends on what you want, if you like having fun then I'll go for it, but if its serious I'll rather not drink.