Minority doesn't equal Maid

In many television shows and movies, minorities are depicted in helping roles. I was watching Weeds the other day and realized that the only Hispanic characters were maids and the only black characters were drug dealers, although the main character is a white drug dealer. So many times in the media we are given the Mexican housekeeper who teaches the children Spanish and talks behind the employer's back. Of course, not all Hispanic people are maids and not all maids are Hispanic but I believe it's detrimental to only show that race only in subservient positions.