Second off, there is no Constitutional "right" to serve in the military. People are denied enlistment for being too short, too tall, too fat, scoring low on entrance exams, not having enough education, having flat feet, asthma, etc.
These folks knew the rules when they enlisted and agreed to keep their sexual lives private and then reneged.
"having flat feet"
Actually, they don't do that anymore. You just get special running shoes.
I knew several people in basic and AIT who had flat feet. All that happened was that they got a certain type of running shoes.