Well how else would you suggest people come in contact with the wildlife of this world?

They shouldn't.

Which is obviously critical in making people care about protecting it.

Where is the evidence for that?

Not to mention that zoos also serve a secondary function in providing for rescue animals, and animals otherwise unable to live in the wild.

This doesn't require the animals to be put on display.

Zoos are not perfect, but are very clearly the best compromise for fostering interest in our wonderful nature in future generations, who probably won't even encounter a horse or cow in real life otherwise.

Or we could stop destroying the natural habitats of those animals instead of making a profit with the remaining individuals.