I tried marijuana when I was a civilian college student.
The only 2 Sailors I've thrown the book at as a Divo were because of illegal marijuana usage and "false official statements". In both cases, I busted them for the same reason: I couldn't trust them (and, also, the UCMJ requires me to report their violations). I would have done the same if they showed up to day check unable to function due to a hangover.
Ya'll can argue about the civilian regulations all you want. When it comes to active duty military behavior, there is no room for that bullshit. We lose fine military members for far less, and being a Sailor 24/7 is a sacred commitment. When lives are in your hands, it is a question of honor and duty.
I can understand not wanting to throw an E-3, who smokes dope once while not in a duty status, into Leavenworth. However, the type of person who directly disobeys a standard and widely-supported order required to maintain high standards and discipline when entrusted with the lives of fellow volunteers is worthy of the Big Chicken Dinner or worse.
I believe that those who have strapped themselves to JP-5 and 20mm rounds will understand the true meaning of "zero tolerance" and, as the world's best military, desire to maintain this standard in everything we do.