That woman sounds like a real witch. I think I would write or call the
head of the rescue organization and tell them of her experience with this
person. Just telling someone in a position of authority might make her feel
better and may actually make a big difference all around. Rescue's need
better people than that working for them.

Make the letter as calm & informative as possible to get them to actually
think about the image this woman is presenting to the public.