I was rereading Eliezer's old posts on morality, and in Leaky Generalizations ran across something pretty close to what you're talking about:

You can say, unconditionally and flatly, that killing anyone is a huge dose of negative terminal utility. Yes, even Hitler. That doesn't mean you shouldn't shoot Hitler. It means that the net instrumental utility of shooting Hitler carries a giant dose of negative utility from Hitler's death, and an hugely larger dose of positive utility from all the other lives that would be saved as a consequence.

Many commit the type error that I warned against in Terminal Values and Instrumental Values, and think that if the net consequential expected utility of Hitler's death is conceded to be positive, then the immediate local terminal utility must also be positive, meaning that the moral principle "Death is always a bad thing" is itself a leaky generalization. But this is double counting, with utilities instead of probabilities; you're setting up a resonance between the expected utility and the utility, instead of a one-way flow from utility to expected utility.

Or maybe it's just the urge toward a one-sided policy debate: the best policy must have no drawbacks.

In my moral philosophy, the local negative utility of Hitler's death is stable, no matter what happens to the external consequences and hence to the expected utility.

Of course, you can set up a moral argument that it's an inherently a good thing to punish evil people, even with capital punishment for sufficiently evil people. But you can't carry this moral argument by pointing out that the consequence of shooting a man with a leveled gun may be to save other lives. This is appealing to the value of life, not appealing to the value of death. If expected utilities are leaky and complicated, it doesn't mean that utilities must be leaky and complicated as well. They might be! But it would be a separate argument.

(I recommend reading the whole thing, as well as the few previous posts on morality if you haven't already)