I bet there's a strong correlation between people who let their cats run around outside and people who dislike zoos. Too many people use a romanticized narrative of animals and do not have the tools, mindset, etc. to learn the reality of domestic and wild animals, the reality of zoos (especially versus sanctuaries and such), and the difference between their cultural expectations of what happiness looks like versus what different animals actually look like when they're happy.
Animals need good food and positive stimulation. Most of their needs are on a species by species basis. No, no one is breaking up a family by separating the jaguar cub from the mother. No one is separating the jaguar family by keeping the male separate. If a typical "nuclear family" model is attempted, there will be bloodshed, stress, and probably death.
"But the animal looks sad!" Do you know what a happy animal of that species looks like? Most people don't even know what a happy domestic animal looks like, often leading to unnecessary stress on the animal and injury for both parties. I've had people tell me that my old kitty looked angry and unhappy. They told me that when I took a picture of her cuddling and purring on my lap. If my cat smiles at you? You're about to bleed.
If you're worried about it, take the time to look it up and question what standards of happiness you're imposing on a different species. Hell, question what standards of happiness you're imposing on different human cultures! A well treated animal is a happy animal, whether in a zoo or in a home. If your cat is stressed by being indoors, check out what stimulation you're offering. If an animal is genuinely stressed at a zoo, they have options to go hide and de-stress. Promise.
