I get the feeling that the people who are put off by the flag-draped, patriotic, jingoistic, "America, Fuck Yeah" thing have never really given Cap a chance. Because that is not Steve Rogers. At all.
Cap doesn't fight for the government. Hell, he's probably fought against it more than he's fought on its behalf. He doesn't represent America the nation. He represents America the dream, the ideal. What America was supposed to be, rather than what it is.
Admittedly, that doesn't mean as much to non-Americans, but what it means above all is that Cap (when in the hands of a competent writer) is just a swell guy. He's like America's Dad, trying to lead by example. And punching natzees.