I know what you mean and I can totally relate but there is a difference between "just" cages and places like dolphinariums and animal circuses. Zoos, for example, might argue that by keeping animals in cages and enclosures, they protect them from predators, poachers etc. and I think some species would really be extinct by now if there were not for zoos and other similar facilities, as much as it still hurts of course to see the wild creatures being deprived of their freedom. In dolphinariums and animal circuses though, the animals are kept to be trained and perform for the visitors. So the only thing that the owners of such facilities care about is the profit. Or do you think that bears enjoy riding bicycles, tigers jumping through fire hoops and dolphins giving rides to fat tourists? I don´t think so...