[Discussion] Do you think it is unethical to buy a dog from previous owners knowing it was probably from a BYB/puppy mill etc?

I hope my title makes even a bit of sense! This isn't relevant to me btw I was just thinking about the ethics of buying pups from different placesFor a situation where it is a BYB or puppy mill and the current owner does not have any contact with the breeder, do you believe it is unethical to get the dog knowing it has come from questionable beginnings? Obviously the pup is already alive and you're not buying directly from the BYB/puppy mill, but still....I'm in two minds about it myself and was hoping for some different perspectives of people much more knowledgeable than myself via /r/dogs http://ift.tt/2ss5fMd