Who would dare say such a thing? Why, only Captain America, that’s who.
Go read the context at the above link – it does a tremendous job explaining exactly why Captain America would say what he said, and how he got to that place. Throw in the fact that ultra-patriot and WWII hero Captain America came down on the side fighting against the government in the recent Civil War storyline, and I think Cap might just be my favorite Marvel comic book character. A man who holds principle above all else.
And you thought comics just stories about superheros in capes for little kids! There can be some real depth in some of these books.