Zoos aren't the greatest in general treatment wise yeah, but none of the animals there would survive in the wild anyways, either because they were born in captivity and wouldn't have the knowledge of how to live or because they're injured too badly to be able to survive. So yeah capturing healthy animals for zoos or the like is pretty terrible but in these animals cases I don't see how death is a much better alternative, except maybe for whoever eats said animal.
I just read you went into a zoo to pet animals, you didnt clarify what kind of zoo you went to.
anyways, in my opinion zoos just manipulate ppl to think they are doing sth good and save those animals, when in reality they do nothing.
its more of an ethical discussion if its fine to let an animal die or let it live like an attraction for humans.
I think ppl underestimate what kind of emotions animals can feel.
for example, the monkeys you see in zoos usually have their back to the class front because they feel ashamed that ppl watch everything they do.
you will never see natural behavior with animals in captivity.
but thats just my own opinion, do whatever you want to.