There may be a few zoos who house endangered animals and care for them and plan to release the endangered animal back into the wild.
But most zoos that I know of anyway don't actually keep or house endangered animals so in that case the zoos are not bad for endangered animals.
In my opinion though all zoos are bad for all animals because all animals deserve to have their freedom to run in the wild like they were meant too.
Animals were not meant to be kept in zoos for our viewing pleasure and zoos do make animals depressed just like it would make a human depressed to be locked in a cage and have people come view and stare at them.
Animals shouldn't have to endure that either.
I love animals but I will not visit zoos because I don't support the keeping of animals in captivity because really zoos are just prisons for innocent animals.
The animals meant to be in the wild should not be in prison which is what zoos really are.