The pilots were picked up from replacement squadrons who weren't being picked up by other squadrons.
Nobody but you has referred to the pilots of VMF-214 as being a discipline problem or rejects, you probably picked that up from watching the TV series.
Probably the best Boyington sea story I remember took place around the late 1930's when he was stationed at North Island NAS and got stuck with the duty across the bay at MCRD for some enlisted Marine dance. He got so ####faced instead of taking a taxi to the ferry building to take the ferry over to Coronado he decided to swim across the bay to North Island. This was like around midnight. He took his shoes off, hung them over his neck and while in uniform started swimming. Eventualy he made it to shore, climbed up and found he was back at MCRD, he swam in a circle.
Now Boyington is another topic when it came being a discipline problem. Read his autobiography. He got into a lot of fights and was a heavy drinker. Boyington claims he would take off on a combat mission with a bottle of scotch and would crack the canopy while smoking a cigaret.
Boyington was a muscular husky fellow. He still was when my father introduced me to him around 1958. Like I said he loved to fight. The last time I saw Boyington he was with his daughter, good looking tall blond. This was probably during the early or mid 80's, he had cancer by then and was about half his weight.
I do have to stand corrected, I mentioned that the Black Sheep squadron was VMF-314 it was actually VMF-214.