They have free time, but they are still on active duty. Honest question (I have no knowledge of military down time), where exactly do these people find the privacy to just have sex? Maybe this is effecting my judgment of the situation.
You don't think people in the military spend 100% of their time outside doing pushups or inside sleeping in a big room with 20 bunk beds do you? We go to bars, have wives, take vacations, own homes, etc.
Where do they have sex? Usually in their bedrooms.
(but yes, people on Active Duty never
really have down time. I was called in on several occasions at zero:dark thirty for exercises and what not. Even on leave the govt can (and has) call people back on duty.)