Navy vet here. Eleven years active, 14 reserve. Looks like more Navy vets have issues with McCain than other vets. Maybe because we heard McCain stories from our shipmates back in the day, and not the kind of stuff that would cover him in glory. The McCainiacs better hope the dems haven’t heard the same stories.
From what I've read, the Left could have access to intimate details of John McCain's time in Vietnam via John Kerry, who attained hero status among our enemies in Vietnam, and who has become good buds with McCain since a long flight they took on a trip together overseas as Senators in recent years.
As you say, stories about McCain have been around since back in the day. It's interesting that he was supposedly conservative politically, yet his leftward views have become more and more apparent through the years, and pronounced now.
There are veterans for McCain. But, there is an organized group of Vietnam Vets against McCain. I don't know of a Vietnam Vets for McCain group. Do you?