Attacking a rival politician's combat record is well out of the norm, even rare, particularly post-WWII. Only one example you use comes close and was less his performance in combat than his leadership of the Army. I can think very few instances where that has happened recently, and the one glaring example that comes to mind was mainly because they made their war record the key part of their subsequent anti-war activities. Even in today's more partisan political environment attacks on a politician's combat record remains rare from political rivals (attacks from random trolls is a different story).
So yeah, still a rationalization.
