My guess, having more than few years military service, is that social engineering is not the biggest reason but plays a role. Fighter pilots, infantry , Special operations etc. are professions pretty heavy on the testosterone for obvious necessary reasons and there is some resentment, I am sure, making them take down hooters calendars is resented, but not the main reason. Not even gays serving openly is that big a problem. Most to them will tell you that gays are less of problem than women because at least they will not become unavailable for deployment or go on light duty due to pregnancy. The whole pregnancy thing is a bigger issue than feminists and many politicians like to admit.

The two biggest reasons are first is drones and precision munitions counting as one and the other is money.

As to the first fighter pilots like to be fighter pilots and fly. Drones have relieved them of many of their missions and indicates there may not be much of a career future for many of them. Precision guided munitions have turned them into little more than bomb trucks. They fly to an area coordinates are fed into the bomb guidance system they release the bomb and it does most of the work of getting itself on target. takes a lot of the challenge out of the job.

The Second being money and I don't mean pay. I mean money being available for actual flying. budget cuts mean less time in the air. Fighter pilots , who like to fly naturally, don't get to do it has often. Planes may not even be a available because maintenance and parts also cost money. Of course training and skills suffer as not everything can be done by drones yet-like air superiority.

The money side is nothing new. We went through this during the search for the peace dividend after the of the cold war during the 1990s (only there was no peace). Budget cuts meant less money for training , maintenance (even troops living condition's suffered) etc.. There was also Social engineering going on with Army and Navy replacing basic training with low stress coed summer camp. along with military becoming job corps fore single parents. But actual deployments increased-less money to do more work.

During this time the Air Force and Army moved to address their serious retention and morale problems. With a remarkable display of a lack of leadership ability by people who attained such high rank the Air Force went with new Navy officer style uniforms (A failed attempt that cost a lot of money) and old style leather flight jackets for pilots, which I am sure upset PETA. The Army decided to buy everyone a new hat-that stupid looking beret.

The real fix is money but despite what you read on Fark things like the F-35 are other weapons procurement a re not the money problem they are made out to be as that spending is drawn out of many years even decades in the case of ships. One of biggest, if not the biggest, yearly costs in the military budget is personnel This not limited to just pay, benefits and housing but also training them. Troops that are well trained have less morale and discipline problems. Good training cost money for things like live ammunitions (the best training) as well as training/inert ammo, transportation (fuel). equipment used in training is going to need to maintained , repaired and or replaced. The places and ranges they train on need to be operated and maintained

This is not to say the military budget needs to be increased because like all government spending there is waste. It is getting the politicians and military leadership to do something about that waste and shift that money were it is really needed. For example we have more Flag officers (Generals and Admirals) than we need but you are not going to get them to say that and politicians like the positions of being "gad fathers" or political mentors to these guys. There are many other areas like stateside DOD dependent school system etc. that could be eliminated and save a bunch of money.