It was good slave owners who justified owning slaves. It was the many owners who treated their slaves "humanely" that permitted everyone to own slaves by setting a "good" example. But no matter how humanely a slave's physical needs were provided for, no matter how kindly a slave was treated, a slave was not permitted to be fully human - to make his or her own decisions about their lives.
Good pet owners and good slave owners are the same, and it is good pet owners who keep animals enslaved to us because if every pet were treated badly, the case for no pets would be unmistakable. No matter how well we treat animals, we are enslaving them by taking away their choice to live their lives as nature intended.
Only when it became clear to enough people that slavery was immoral in itself, and no amount of "good" owing could justify it, did slavery end. The only hope for animals is for that to happen for them.
For God and Nature's sake...let them be. Let them live their lives as they were created to. We have no moral right to own other species. We have no moral right to use them in any way, not even for companionship.
Dr Danten wrote: "Animals honour us only when they are truly free". No matter how good and kind we are, we stop disgracing ourselves only when we stop owning other species.
Follow the pointing figure honestly, without hiding from the truth, and the finger almost always points back at oneself.... all we good pet owners are the problem.