This is their tactic more than out-and-out lying, they take advantage of your lack of experience with the rules, regulations and verbiage. And they are your only guide through the red-tape, so you follow.
Similarly they told me the job I wanted (computer programming) was not available because it was full since so many people wanted it and recommended electronics on attack helicopters as it was at least technical. (So I did it.) What they didn't say was that new classes open every week, so while the one he showed me was full, the next one wasn't. (Had I balked I believe a class would have had a "sudden opening".) Or that while there were technically electronics it was really just black box replacement and the real work was on the weapons themselves and involved little to no relevant electronic experience.
Again... not out-and-out lies, but certainly to the military's benefit more than your own.