there's a whole genre of criticism, which is especially prominent in politics, that amounts to "you said something contradictory one time". this is ok as an argumentation technique, but really falls short as an indictment of a person or group's ethical character.
hypocrisy is a kind of social faux pas, basically. a person not living up to their own ideals in a publicly visible way. it's been a long time since hypocrisy bothered me. which one of us lives up to our ideals as often as we'd like to?