How do we know that he was an honorable and stoic prisoner? We only have his word to go on.
Everything in his life since being released has been whoredom. I don't assume that he was a noble man before and during his imprisonment and just suddenly decided to become a pig after getting freed.
The other prisoners at the Hanoi Hilton have told his story more than he has. To this day he cannot raise his hands over his head because his shoulders were so severely dislocated by torture. He was offered the chance to go home early and turned it down because others who were interned longer than him were not being sent home. That is heroism that does not grow on trees.
His adultery after his release from Hanoi is another story. If you want to criticize him for that be my guest. However, I think it is ridiculous to mock him for what he endured in Hanoi.