You're kidding, right?
The sex of the miscreants is not the problem..
The CHARACTER of the miscreant guards is the problem....
Federal Employees, with responsibilities such as this -- should be capable of lawful behavior and keeping their dicks in their pants while on duty.....
Semper Fi
Not kidding at all.
While I agree with your comments, it is a great deal easier to sort applicants for the position by their sex than by their strength of character.
Per your signoff: The Marines are the only branch of the military that has sex-segregated basic training. All others have integrated basic, and have had sex scandals as a result.
Going by your criteria, apparently the Marine brass don't think they can find potential drill instructors with the ability to keep their pants zipped while on duty.
Or perhaps they recognize that attempting to win an argument with biology is not a good idea.
While the guards involved here should be punished to the fullest extent, I would be surprised if the idea wasn't brought up by inmates who wanted the booze, etc. Leaving men in constant contact with women coming on to them is not a good idea. (If you want the men to continue to think straight.)