I wouldn't dare call the war a botched effort, because I don't know enough to do that. But there is a popular conception, even among some veterans, that it was mishandled by the government. My point is that Kerry's position finds some resonance with that conception, and looks credible, maybe even courageous, to those who hold it.
I agree that Kerry should recognize that the veterans who serve deserve honor. He seems to have fallen in on both sides of the fence: "I served in Vietnam and am a decorated hero," and "I opposed the war." This dichotomy needs to be explored, because right now he's cashing in both ways.
Incidentally, if the war was mismanaged by the government, that is no discredit to the boys, girls, men, and women who served.