Very few people would be capable of enduring torture across nearly six years, while letting numerous other prisoners go free in their stead.
McCain signed up to the military willingly. He comes from a family line of professional soldiers. Who knows how many of those others he put before himself were forcibly drafted into it, plausibly many of them (late 1967 was near peak US troop levels, a lot of soldiers taken POW at that time forward would have been drafted; in 1968 300k were drafted, 1.7m total across the war (38% of which served in Vietnam)).
Personally I'd never agree with the US involvement in the Vietnam civil war. McCain is a hero for his actions in captivity, not for his war fighting.