You got that right... McCain must answer to the POW/MIAs and the way he treated the families of those left behind and his kissing the ass of those who held him and the other POWs at Hanoi Hilton!
He has something to hide and the way to escape that is to come out strong about Kerry using his Vietnam experience and then not wishing anyone to question him about it. McCain does not want anyone to really question him either, but do a search on McCain and you will see what gives.
Remember Admiral Stockdale wanted to prosecute an officer for collaboration but never would say who. He was suspiciously given a star and after that, nothing else was ever mentioned.