Oh, for heaven's sake...
Cabin crew recruitment selects for gregarious, energetic, young people who then get thrown together in an highly technical environment with all the stresses and boredom of dealing with hundreds of irritable punters for hours on hours, get their body clocks messed with and finally get dumped en masse in hotels in unfamiliar cities. Combine that with the UK's drinking culture, and what else is going to happen? (Yes, I know what else happens!)
We've all seen hung-over CCs on morning flights - or perhaps they were just fatigued due to rostering, timezones or any of the other factors that affect humans when operating in the highly un-natural business of running around the planet at Mach 0.9. From my point of view, it doesn't really matter what the factors behind reduced performance are, it matters what the practical risk is - and I don't offhand know of any accident where CC impairment was a significant factor. So the practical implications, while serious, are limited.
I'm not saying that cabin crew don't need to be sober, rested and alert on the job: of course they do. But until the culture of the job is changed - a culture largely created by the airlines - incidents as described by this thread will continue to happen, as surely as putting fuel into a jet engine produces exhaust gasses as well as thrust. Moral outrage is misplaced and unhelpful.
R