Barry smeared his uncle when he tried to draw a link between his experience at a death camp liberation and post traumatic stress disorder (living in the attic).
He thought he could toss out a few statements and be done with it. He didn’t actually want to debate the issue, just tarnish the troops.
His main goal, IMVHO, was to suck up to the Jews since he knows he’s in BIG trouble in the Jewish community so he figured he could kill a bunch of weaknesses w/ one stone; jews, veterans and attempting to claim his family is patriotic.