I guess it depends on what you mean by democracy. If you think that democracy is basically the election of representatives by "the people" and are trying to score some points with that old saw about the hypocritical United States, then I suppose the existence of superdelegates is not very democratic. If you think that democracy is the constant negotiation of who gets to be called a citizen, of who can be democratically excluded, fought, killed, or whatever, then the existence of superdelegates is extremely minor, a small administrative procedure, an aesthetic blemish rather than a political matter.