All they said is that the dog came from a puppy mill, not the rest of the circumstances that led to their husband getting the dog. You assumed "came from puppy mill" meant "purchased from puppy mill" when it could have been seized from a puppy mill and that's how it ended up in s shelter, or another person could have been the original owner and the shelter had the dog's history and was able to say where it was bred.

You're assuming they used "rescued" in bad faith just to accuse them of using it in bad faith when it more likely implies one of the other options.