I'd argue it's not either or, one needs not be under the influence at all times, in which case I'd agree that it would not be good, at all, the kind of disconnect that would come from it. my point is that in certain social situations, such as going to speak with someone you like but being inhibited, alcohol might facilitate a first approach, if more times than not this leads to a relationship with offspring that would not otherwise have happened, it might be net good for the continuation of the species