Unfortunately it’s not at all uncommon for moral and scientific questions to get tangled up in this way. Let me give an example from a different domain—perhaps the most blatant example of all: the question of whether life begins at conception or at birth. That looks like a scientific question, but it really has no scientific content whatsoever. We understand the process of embryonic development in great depth and exquisite detail—attaching the label “life” at some timepoint would not add the slightest iota to our scientific understanding. We all know, of course, what this question is really about: it’s about whether abortion should be permitted. It is really a purely moral question, disguised as a scientific question.
Why do moral questions get disguised as scientific questions? Basically because it is useful as a debating tactic. Arguments about right and wrong often depend on axioms that are not shared by other people, so they tend to degenerate ultimately into hand-waving and shouting. If an argument is about objective truth, though, everybody who knows all the facts ought in principle to get the same answer. I’m not saying that people who argue about the beginning of life do this deliberately or understand what they are doing—obviously they don’t. But the upshot is the same.
William Skaggs (in “How Could We Recognise Pain in an Octopus? Part 2“, Scientific American Blog)
Basically saying that you do need to understand science in order to form a conclusion about the morality of it, but the moral conclusion you form isn’t a scientific conclusion. It’s informed by science, but science can’t answer moral questions for you.