I guess I don't have an issue with any normal slang for breeds. I don't like "pibble," and I worry about the people who use the term viewing themselves as pit bull advocates, but that's about it. I don't use "pit" or "pittie," but they don't really bother me.
I say "heeler" and have never known that people had an issue with it until this thread. I was introduced to the breed in Arkansas, so maybe that's why. But a lot of people around here say it. I regularly have to tell co-workers that the "heeler" someone wants a grooming quote on is in the computer as an Australian Cattle Dog.
So normal nicknames... are what they are, I guess. I mostly just have issues with people who can't say or write the kind of dog they have (Shiatsu, Lopso Apsa, Rockwilder).