[freehunter]

>That said, I've never really seen a consistent argument against _protecting_ prey animals from lions (and letting lions die out).

You might begin your research into this subject with reading about the reintroduction of wolves into various locations where they had been eliminated. The prey populations always fare better when there are predators around them. Without the pressure of predators to balance the population, deer and beaver and other prey animals tend to over-populate, which results in damage to the environment (over-grazing) and then eventually starvation of the prey animals.

The deer are either going to be killed by a wolf, killed by a human, or killed by disease and starvation. At least the first two options don't also cause extensive damage to the environment before they happen.

https://www.yellowstonepark.com/things-to-do/wolf-reintroduc...