Edit: rcsa, just read your post. I think there's a difference between having a couple of sherberts to relax yourself before 8 hours kip and getting totally trashed to get to sleep. No one should have to do that in an attempt to be compos mentis to do their job the next day and as I said operators should be held to account.
Completely agree with you there - but I don't think we're talking about a pilot turning up totally trashed. We're talking about him being over the blood/alcohol limit. On most people's metabolism, a couple of glasses of wine and a scotch will still show up as "over the limit" eight or nine hours later. That's much more in the "couple of sherberts" league than the "totally trashed" league.
Looking at an earlier post I think there maybe some degree of 'can do' in the make up of a pilot, of not wanting to appear to be failing the company, of not wanting to be seen as less able to hack it than fellow pilots.
I guess it takes an alpha personality type to (a) want to do the job (b) be good at it and (c) thrive in that environment. There are a few other occupations where that is a necessary trait. But in fact it's not a critical characteristic in flying. Perhaps in a crisis it's a useful trait (though even that's doubtful - the critical skill in a crisis is the ability to stay calm).
But I suspect that the alpha culture is a hangover from the "good old days" when civilian airliner pilots were all ex-military - and of course, there's no place for risk-averse pilots in military flying in wartime.
Tom Wolfe makes an interesting point in his book "The Right Stuff" that the uber-calm, growly, tech-speak pax announcement made on every sector by every pilot in the world is directly descended from the way that US military pilots were encouraged to speak to tower - and other aircraft - in WWII; and that this was how Chuck Yeager spoke during his early flights to the sound barrier, and subesquently to the edge of space. That's alpha flying!
I've noted elsewhere on pprune that I believe one of the elements in the risk matrix that makes former Soviet aircraft so inclined to crash is that their aircrew are suffused with the "can-do, ignore the problems, fly on the red-line (especially with a little vodka lubrication)" attitude of the Sov and Sov-successor militaries.