I must say, I find that surprising. Afghan men, approaching Western women in my experience, tend to be embarrassingly awkward and frankly - laughable. Perhaps the forced proximity of a military base differs - or perhaps your typical Afghan hires are different to my own.
Western women complained of Afghans staring at them, or making awkward comments, but I never had one actual incident brought to my attention of an actual concern that was a complaint/concern worthy of a firing and/or some sort of 'hearing'. My span of control was 90 Western consultants over 13 projects, and 330 Afghan staff. Approx 30-40 consultants at any time were women.
It is almost like they were a separate gender. Afghan males by and large, to my observation, had no idea how to conduct themselves around Western women. My hunch is that if complaints on military bases were common, was that people interpreted an awkward or strange comment as being an assault.
Please do not interpret this as being an endorsement of rape, or somehow insensitive. It is simply a fact that Afghan men generally have no clue how to address someone of the opposite gender, and the culture generally is very blunt and direct. If an Afghan man complimented a woman on their breasts, they need to be given a degree of the benefit of doubt. If a woman is uncomfortable by this attention they absolutely should draw the line in the sand and tell them this is unacceptable.
In my practice, there was probably no mechanism to levy a charge of 'sexual assault' - however on a military base with all the relevant niceties & structures, I suspect the opportunity is there.
-AH.