The reason we speak of "moral dilemmas" is that when it comes to questions such as whether we should kill one to save many we are confronted by competing values.

Is the best course of action the one that "maximizes the greatest good for the greatest number"? Do ends always justify means? Or are there limits on what is permissible? Do people have rights that must be respected? An intrinsic worth than can't simply be added up? And what about the importance of our attachments? What about love? Philosophers have explored and illuminated this space of values, ideas and conflicts for eons.

The upshot is that there are no algorithms, and can be no algorithms, that let us regiment these different competing values and lines of reasoning. This is why we should not speak here of moral responses, as if one's more opinion were a kind of reflex action or gut feeling. It isn't a moral response unless it is a judgment, and it isn't a judgment unless it is sensitive to reasons, arguments, counterarguments, examples, as well asemotion and feeling. That is, if it isn't sensitive to the fact that these are hard choices, real dilemmas, where any judgment call you make is just that, a judgment call about which there can be well-meaning and intelligent disagreement.

It wouldn't be a hard choice if what to do is straightforward.