Cynical, even maybe misanthropic, and definitely very critical of post war American notions of right and wrong and history.
Graham Greene was always skeptical about the Americans, and always felt that they were more dangerous than the Europeans. Third Man is yet one version of this; Quiet American, another.
But conservative?
I don't think Harry Lime's speech at the end is meant to be anything more than the self-serving drivel it is. But the beautiful woman walks right by Joseph Cotton because he's a fool and has the virtuous convictions of a man who has been tested by nothing.
Joanna