Cal_kashi 
No, it is because you didn't disclose it. That makes you a liar (by omission), and why you get DQ'd....and I get disqualified for not listing the one time I tried marijuana a few years ago. Apparently it's ok if you try drugs when you're in your experimental teen years, but if you try them later in life then it surely must have been for recreation and you're a junkie and a liar. Like we all follow the same timeline in life and you're only allowed to do certain fuck ups at certain periods in your life.
That's the exact same way a lot of people lose or are denied DoD security clearance. Honesty is appreciated, don't hide anything, that's how they know they can trust you...which is the whole point. Not declaring that you had a previous bankruptcy (implying money troubles and potential for being bribed or bought off), trips to "hostile" countries, misdemeanor infractions, etc. All of them carry similar weight during the evaluation.
It's not what you forgot to disclose, or even what you did, it's that you didn't disclose it.
