I agree that one glass here or there will not hinder progress, and high fives to those who have the will power to say "no more" in social situations.
However I do believe it's important to highlight that there is a fine line between alcohol having no effects and having detrimental effects.
NHS studies have shown that one glass with your sunday meal can be benificial to your health. But two glasses overwrites those benifits and actually becomes something negative. This sort of alcohol once in a while won't leave any lasting detrimental effect on the body or mind, but regularly taken over a long period of time will be detrimental to body and mind. I knew a lecturer while I was at uni who had a glass of wine everyday with his dinner and he had significant health problems, but didn't have the will power to give it up. *edit* (he was in his 70s)
Wine glasses in the UK have actually increased in size, so one glass is actually equivilant to 1 and half.
So while I agree that we shouldn't prohibit alcohol (I favour "abstain") I do not think discussion on the matter to be silly.
I mostly agree with what you say. People need to act responsibly. If we don't know how to behave when it comes to booze, we're in deep shit as this is a minor challenge among the many we will face. For some people though, alcohol is a big problem and they should stay clear, Buddhist or not.
As with every action, we should try to foresee the outcome. The same applies when we drink. If by ingesting some beverages we get a better health and don't hurt ourselves or others, there's no reason for us not to take it.
The discussion of the matter itself is not silly. Silly is someone arguing that a pint or a glass of wine will block realization (unless in very specific cases). I should have been more clear. If someone took a vow, then it's also little different, because such person is betraying his own commitment and this may have a psychological effect the next time someone is trying to uphold something. But in the good spirit of Buddhist moral, our actions are mostly evaluated by the intention behind them, the skill applied and their consequences. Knowing that, it should be obvious how are we to see this whole issue. This doesn't mean, however, that if someone wants to take such precept as a training method such should be discouraged. There's a place for it also. Nevertheless, considering alcohol nasty per se and, as such, off limits to Buddhists is plain worthless puritanical mentality.