Why are we as a supposedly civilised species, okay with animal slavery
Whether it's animals in zoos for your viewing pleasure, sedated animals for your holiday snaps, animals locked up for your riding pleasure. Why are we all so okay with animal slavery?
You are presupposing that people view animals as equals. Even though some people (including you, presumably) do believe that animals deserve the same respect and dignity as humans, the vast majority of humanity does not. Until a significant number of people feel the same way, this is unlikely to change.