The problem is not ex-military pilots per se, as there are many very fine and capable ex-mil pilots both at Flybe and elsewhere (and yes, some of them even flew fast jets back when the RAF actually had cash to go flying). The problem is people who have an inflated sense of their own worth, can't handle advice or criticism and little or no ability to manage relationships with others. This problem is not exclusive to aviation either.
Unfortunately pilots, and more particularly the a/c commander, are effectively operating as managers, yet most have absolutely no training or experience in this area. It often leads to problems with inter-crew relationships on both sides of the door as this is one area the pilots can't resort to a checklist and some fail miserably in attempting to manage the issue. I doubt there is a single airline pilot who hasn't witnessed one of their colleagues make a complete fist of managing a crew issue, or even done so themselves. I know I have.