The thing is that, 999, that stereotypes of appearance and naming are more difficult to avoid. Often those stereotypes exist because those names and physical features tend to be more common in the stereotyped group. They're not the truth about the group, but some people in the group do fit them. So, for example, if a writer has a character named Patrick who's Irish, redheaded, and speaks in a thick Irish accent and uses stock Irish phrases, would he or she necessarily be just reinforcing the stereotype? because it's not like there aren't Irish people who are redheaded and have thick accents and possibly use stock phrases. Of course, my question is more about appearance and only a little bit about dialect, but the example is similar.