Very true, Anyone who as ever served in the armed sevices in a third world country will tell you that sex in the village was rampant and readily available and it was all hetero. No queers when you can screw all night with one of the natives for 20 bucks or less.
You refer to young men, 18-24, in an environment that is itself very rare. What some people may be willing to do in their youth, they should mature out of, hopefully they did.
I will still say that few men, across the board, all age ranges, want to engage in promiscuous sex with a woman who has just engaged in sex with a dozen other guys, or a woman who does so on a regular basis.