Before invoking any moral or philosophical principals, I'd consider the PoV of wildlife & natural area professionals. They know the public can react strongly to situations proximate to charismatic fauna, or "morality play" scenarios. But the public's actual appreciation of animal behavior, ecology, and natural area issues is little beyond "parks are pretty" and cartoons about anthropomorphized animals.

Meanwhile - gov't funding and support for real-world animal, ecological, and natural area work is paltry, with many critical problems neglected.

And trying to somehow force lions to be monogamous, and hawks to be vegetarians, and cuckoos not to abandon their young, and etc. is the sort of idealistic black hole that all their funding and support could easily be poured down - with less-than-nothing to show for it.