Is finishing last in your class and defending your country now considered worse than avoiding service because of a cyst on your butt? Rush's father, Rush Limbaugh Jr., also had a pilonidal cyst, but that didn't keep him out of the service. Rush's father was a fighter pilot during World War II, flying a P-51 Mustang in the Pacific Theater of Operations.
Actually yes. McCain didn't have the aptitude to be a Navy pilot and if it wasn't for his "family" connections he would have never been allowed in a plane.
By allowing a person who didn't have the aptitude to be a flyer, become one because of ego, is much worse than a person being "4F", IMHO.