I had someone come into my office complaining about watching their friends yorkie. He said that the young male pup would hump everything in sight, pee everywhere, take off running the second he got a chance, and would even try to start fights with bigger dogs. In addition was crazy hyper and would jump all over anyone he saw. He then went off on a tangent about how he couldn't believe his friend would even pay for a "stupid little dog" anyway, and when I mentioned I also had a yorkie he tried to play it off. Then he started asking about Rizzo and I said he was the exact opposite of the dog he was watching because he was trained starting as a puppy and has been neutered. Apparently the owners of the dog he was watching "paid a lot of money and plan to breed him to get their moneys worth" which is why he isn't neutered. I told him that the dog's owners were crazy and they should neuter him, but I doubt he passed on the message. I just feel bad for the pup, what if he does get out and starts a fight with a big dog
I strongly dislike greedy people, and try to educate when I can, but you can't force knowledge on people.
I think you handled the situation as best as you could, he probably just thought you were nutso for "fixing" her.