Wait, I didn't make any ethical argument??

But I can shed a lot of light on ecology of the wildlife conservation.

Just for OPs benefit, I'll throw a little basic info about what they're going for to show that this is the exact type of conservation efforts that will always benefit the populations in the long run.

So, each species has a given carrying capacity in the environment.

Mathematically that's denoted as K.
It's the maximum number an ecosystem can hold for any given species.

Something like a lion or a cat is said to be K selected, and something like a zebra or a mouse is said to be r-selected.

Here's how they decide how many animals to cull:

Check out Fig. 5 in this link

On that graph there is a place on the x-axis marked K.

That graph is a line that represents how a population would grow under normal conditions. Meaning that it isn't growing exponentially, it's growing logistically.
K is the carrying capacity of the habitat. It's the number of individuals of a species that can be supported by the habitat.

K-selected animals would have a population around K. They have stable populations and relatively low mortality and will generally hover right around where they should be.

They are called K-selected because they are selected for populations right around the carrying capacity.

r-selected species are 'rate-selected'. So they are selected to be growing at a maximal rate. That's because they are usually something like mice that will have huge mortality, so the individuals are all pumping out as many offspring as possible.

r-selected organisms will generally have a population right around K/2. That's because that's where the slope of that line is steepest, so that's where it's growing fastest.

(To clarify, each species would have a different graph. So the mouse would have a different graph from the cat. The mouse population would be at K/2 for the mice, not K/2 for the cats.)