Animals kept in captivity, and as in pet stores being bred for that, to go to being sold, to anyone who will pay, is not ethical treatment of animals. It may be better than slaughterhouses but that isn't saying much. There are other unethical ways animals are treated besides in slaughterhouses, and being held in captivity to be sold to anyone without any checks, while being bred for that, is certainly having unethical treatment of animals. Humans want freedom, animals should have that as well. And certainly there are animal sanctuaries, but there should be many more, for animals who cannot have reasonable abilities to survive in wild environments to still have what freedom there can be, which billions of animals that there are in captivity would want.