There are a number of theories.
McCain critics believed he was blocking access to non-returned veterans or documents that had comments about his collaboration with the enemy while a POW. I’ve visited the Hanoi Hilton and his jail cell in a Christian mission about 5 years ago now. It was a terrible setting. On the other hand, he did participate in some communist propaganda, I’ve been told. I don’t recall it. The explanation is that torture gets you to do things you don’t agree with. I can see that. I know its true. Waterboard, for example, does work.
On the other hand, inexplicable types of collaboration to exist, and the conspiracy theorists said there was that kind of damning evidence against McCain.
McCain’s supporters always stated he did it to protect POW families who didn’t deserve to have old wounds opened up again.
“McCain’s supporters always stated he did it to protect POW families who didn’t deserve to have old wounds opened up again.”
Except having a POW family member is a current wound until the day they come home, dead or alive. McInsane prevented either of those options. 1,240 or so POWs left to rot in Vietnam because McInsane sold out to give Vietnam Most Favored Nation trading status.