By making a generalization, you place yourself in a defensive mode when people disagree with you and you have to explain your way out of what you said. So, I think that making generalizations would not be the proper thing to do on any issue. Do I do it, probably, but that does not make it right to do.
As far as stereotypes, this can be inappropriate as well. I disagree with Brian when he says they are accurate. Where some people may fit into a "stereotype" there are others that don't fit and stereotyping everyone shows how shallow in our thinking we can be.