I do not know how old the instructor is but if she is an AKC judge then she has been in the show world a while.
In the past, Basenjis did tend to have sharper temperaments and they developed a reputation for being aggressive to people and to other dogs. Handlers, judges, other exhibitors, coursing enthusiasts, and veterinarians who were around "back then" may have had negative experiences with the breed. Many of these people never "got over it" and they still have a strong dislike for the breed.
The best way to change a person's attitude about the breed is for them to be around nice, friendly Basenjis. You already said that the instructor was mellowing towards Pippin so perhaps your puppy may be the one to improve her attitude to the breed.
Of course, if her negative feelings are too deep then it may affect Pippin. I would try at least one more class and see how you feel about the interaction and behavior of the instructor at that point. Remember though, puppies tire fast and then they get cranky. If Pippin starts to get that way it is better to leave early. Or, if he is ok in a crate, you can crate him in the car and go back and watch the rest of the class.
Edited to add: I don't think she meant the puppy's behavior was not acceptable but rather your behavior. You should never drag a puppy. Coax him with treats and praise to get him moving.