What was McCain’s motive for covering up the location of MIAs?
McCain’s motives seemed to be political. Our government didn’t want us to know that hundreds of men were left behind in Vietnam. If McCain were to disagree he probably felt his political career would be over. Certainly they would try to discredit him. You can find more complete information here:
http://www.theamericanconservative.com/articles/mccain-and-the-pow-cover-up/
When the French lost their war there hundreds of prisoners were held back. Eventually the French paid ransom for them. It was generally felt we would be getting the rest of them back. If you read about the evidence it will make you sick.
BTW McCain was very cruel to some MIA families. He is an evil man.