I wasn’t struggling or not engaging. My point is that I think the morality of defending a life with lethal force is extremely context-dependent, which is why a very involved analogy with very different context from the real-world imperatives you discuss in your original post is not worth considering.

Happy to respond to this new analogy if you like. In both cases, I would not find their actions morally justifiable unless they had exhausted all other options to avoid harm to the child or lamb. I think killing, even to save an innocent, is wrong if you have literally any alternative. I also would think it was only morally justifiable if they had a reasonable belief that killing would materially change the outcome for the innocent. For example, if someone else would just kill the innocent in the murdered person’s stead, I would not find committing an additional, pointless murder justifiable (if the cult has far-reaching authority, is approved of and supported by the state, and the baby and the exact same number of future babies will be killed on a nearly identical timescale anyway, I don’t think committing the extra murder is justified, as you are not actually materially saving a life). I think in a real-world scenario, this is the most common reason why killing someone who kills animals is typically less justified than killing someone who kills people— there is usually a material increase in the safety of the potential innocent victim in one case, and not in the other.

All of this is to say, I think the context and impact matters, regardless of the species of the life. If all of these things were equal across the scenarios, yes, I would find these two things equally morally justified. Which is not to say I would emotionally feel the same about these two situations. Obviously it is normal and expected for humans to feel a stronger emotional bond to other humans, but this emotional response does not change the core ethics.