When you´re in a hole, stop digging.
Someone in the field let off some pressure by going over the top in a private email, it happens. There was no Blue-on-Blue, nobody died, there is no need for an investigation by anyone, especially the press.
This was a 10 minute piece on a slow day blown out of all proportion. The press and public aren´t interested any more. No rebuttal needed, and it would just be seen as sour grapes anyway.
Just let it die, and buy the Major a drink if you ever see him.