Maybe he was “progammed” in the “Hanoi Hilton” to behave “that” way. Remember Johnny Boy was an Admiral’s Grandkid and Kid so he probably(I surmise) did not have to endure alot of “trails” growing up so any hardship he had to endure in a POW Camp were magnified.
Kinda like Nick Brody in the Homeland TV series.
Wonder if the writers of that show were patterning it after McJuan?