It sometimes occurs to me the same but with the ethicalness of zoos. That it's cruel to keep animals in captivity but then I think, most humans are living in a form of captivity. We can't necessarily survive the temperature outside so, we live inside. And, we have to work to earn our keep- usually indoors too. How much freedom and access to nature do we have either? Ok, we are able to choose to leave but, not permanently. Not at certain times. Not without money- unless we're ok with being homeless.