His pride hurt (he stated he resented now being given an ear by the White House on how to conduct the war), he is now venting his spleen and the gases it contains.
A shame, too, is that he will be remembered now not as a hawk Democrat in an age in which the Democrat Party is mostly anti-American, but as a foil of victory and an aid to he enemies of the United States.
I think it's dubious calling someone a "Democrat hawk" when the person has for sometime been diverting funds for the military to his own pocket via his friends and relatives. That's not my definition of a "hawk" of either party.