I don't think this is because of scope insensitivity, or because I am not a utilitarian. I endorse utilitarian ethics for the most part, but think that "malicious preferences" have zero or negative utility in their satisfaction, no matter how many people have them. For conflicts of preferences that involve things like disputes over use of scarce resources, normal utilitarianism applies.

Ah, okay. This sounds somewhat like Nozick's "utilitarianism with side-constraints". This position seems about as reasonable as the other major contenders for normative ethics, but some LessWrongers (pragmatist, Will_Sawin, etc...) consider it to be not even a kind of consequentialism.