I agree with you 100%! And not only should they know how to correctly spell the name of the breed, they should at least know something about it. Man that irritates me.
I have a shih tzu as well and had someone who "used to breed those" tell me that if I trimmed his hair he would go blind!
Oh, and she also informed that Norman is an "Imperial" shih tzu. ("Imperial" is to the shih tzu world what "teacup" is to the yorkie world btw)