He has another problem that induced him to make the remark--he virulently hates America, the military and all both stand for. The wonderful, heroic Swiftvets were and are the real men. In Kerry's view they did the absolutely inexcusable; they exposed him. In doing so they stood for the entire military. That redoubled all the bitterness and hate he feels for the military. Thus, when he was with a friendly audience containing many traitors who agreed with him it was just as though he'd consumed enough drinks to loosen his tongue but not enough to slur his speech and he said what he really thought, exposing his complete contempt and hatred for the military and America. Unfortunately for him and the DemonRats, most of whom feel exactly as he does, he ignored the all seeing eye of the TV camera. The rest is history.
I believe there is no doubt he hates American and the military. He adequately proved that when he joined with Hanoi Jane Fonda to attack and lie about our military way back when.