My initial reaction to the news was surprise that these astronauts, on what would be the flight of a lifetime for any pilot and for which civilians are paying millions of dollars, would dull their senses with alcohol.
Then I thought about "The Right Stuff" and the part about "spam in a can" -- nothing under your control and you die if anything goes wrong -- and why not be drunk then? That seems to be the spirit (ha ha) of the earlier posts in this thread.
But I think what may be happening here is career disappointment. These astronauts joined the program 20 years ago, figuring that by now they'd at least be the airline pilots of space, probably flying to Mars and doing all sorts of groundbreaking things. And what is the peak of their careers? An orbital flight (or two) of the sort that was cutting-edge in the 1950s. Any excitement seems to have to do with whether the spacecraft was damaged too much during launch to return safely. Sometimes there's a spacewalk TO THE OTHER SIDE OF THE SHUTTLE to see if that's so.
Let's hope the new commercial space ventures will change things.