elephants evolved without predation

Really? They just jumped from rabbit-sized mammals to elephant-size with zero predation?

Prey animals breed with the assumption

This is the first time I've heard of a deer "assuming" anything.

If this doesn’t happen then their population balloons until it consumes all available resources, then it collapses.

Evolution doesn't stop simply because predation stops. Yes, deer population will expand if predation stops, but that expansion will not result in some "Reindeer Apocalypse" as the colonialist brain-trust on here is trying to pretend it would. No, it will not result in the consumption of all available resources, as reindeer's natural environment is vast frikken northern hemisphere continents. If that could be possible, you might as well try to prove that bison hoovered up all the world's grasslands before humans even managed to become humans.

Let nature be natural.

We closed that door permanently about two centuries ago. We did...

We’ve removed their natural predators,

...this, remember?

It’d be fascist to assume it’s our domain to conquer and dominate into submission.

I'd say it's pretty eco-fash to assume that this isn't the exact thing we've already done.