Why does McCain being a Pow have any bearing him being presidental material ?

You will have noticed that he refuses to make his military record public. Things happened in connection with his capture and sojourn in Hanoi that he can't let the public find out about. He was a POW, He was not and is not a hero as his propaganda machine has been claiming ever since he was carried moaning and limp off the plane from Hanoi in the Philippines.