The article makes some interesting points, which I think could be applied to BUYING your dog, but in the case of a rescue dog, the ethics are very different.

My dog was bred to race but sucked at it. Had she not been rescued and adopted, her life would be substantially worse than it is today, assuming she survived at all. It's pretty hard for me to imagine a negative analysis of our arrangement.

The author also makes a distinction between pets and working dogs, as if owning a dog to corral your sheep is somehow more ethical than having one for companionship. I don't get this part at all.