See, I don't see things in black-and-white, good-and-evil in the political arena. I'm disillusioned with both major parties (and so am not a Republican either). Being a political independant means I can support the troops, and even the mission, without supporting the cult of personality. Gen. Zinni, for instance, is not anti-war. What he's saying is that, if we're going to salvage this mission and make it a success, it will require some serious strategic changes. If he's right - and unless you're a flag officer, you're not qulified to determine that any more than I am - than he has a moral duty to speak up now that he can do so. It's actually the patriotic thing to do.
Even Emperors need someone to tell them "Remember that thou art mortal." It's not disloyal to tell the President that he's made mistakes - even huge ones.