A worry about democracy

Let me at once say I think democracy is broadly a good thing -- and optimistically, a very good thing. My worry here would be better expressed in terms of a distrust of utilitarianism and baldly utility-based decision-making. One of the problems with utilitarianism, I think, is that people are often too incurious about a) other people's interests b) other alternatives to those presented, to make well-informed utility decisions. Democracy (both in the act of election and the distribution of interests by elected officials) is at a basic level, a simple utilitarian calculus. In simple language, it's basically a '51% thing'. Market crashes and the election of questionable governments by popular majority -- both occurrences that happen time and again in history and the present -- seem to be good evidence that crowds are not always wise about their own interests, let alone those of others.