In some ways, exposure from TV or films is better than no exposure at all, because it does provide a human example. However, its problematic to base ideas of people of a certain racial or ethnic (or any) group on characters from a movie or TV show. If you had no exposure to white women would you want Sex and the City to be your idea of what all white women are like?
In other words, your thought has a little merit but is also grossly limited, I believe