"Utility" in this sort of discussion is a philosophical jargon meant to encapsulate everything that might go into a rational creature's decision-making process.

"Utility" in this sort of discussion is a philosophical jargon meant to encapsulate everything that might go into a rational creature's decision-making process. I.e., reason or experience may be able to tell you what actions will lead to what results, but you need something else: You need to know what results you actually want. So the goal of every rational being is to maximize its utility; and utilitarianism, a popular ethical system, defines morality as choices which maximize global utility. In economic jargon this would be "preferences"; in more everyday language it would probably best translate to "happiness". So yes, in this sense, every hair color has a "utility", in the sense that it will make the person who has it (and the people around them) happy or unhappy to some extent. It doesn't matter why you prefer redheads to blondes -- whether it had some evolutionary advantage now or in the distant past or whether it's just a random chance; you prefer one more than the other, and so the one has a higher utility.