There are a lot of different kind of zoos, but yes general rule is that if the zoo is good for human visitors it is not good for the animals.

Let me elaborate.

There are zoos which are more designed for the animals, i.e. Korkeasaari in Finland, but the problem is that it is not so visitor friendly. For example you rarely see the big cats, because the cats have large habitat, and lots of places to hide. This is good for the animals, but it makes lots of crying children because they didn't see the tiger.

The most interesting zoos for the humans put the animals close to humans and in small cages. Some even let you interact with the animal. This makes the animals live very stresful life.

IMO it is very narrow minded to say all zoos are bad, but in general all the "good" ones are bad

Edit: you can go read tripadvisor reviews to see how it is that many leave 5-star saying that animals look happy and 1-star reviews saying that didn't see any animals.