I think the question is valid. Why should a human have a moral responsibility towards non-humans, while a cat doesn't have a moral responsibility towards non-cats, just because the human is capable of making moral judgements? Is there any analogous situation where capacity engenders responsibility? Are gorillas more responsible for how they use their strength, since they're stronger than humans?

>Being capable of that is, arguably, the sole thing that meaningfully separates us from the (real or simulated) fruitfly.

That's a bit of an extreme hyperbole, don't you think?