I'm really not sure what that's supposed to mean. The current Miss USA is Lebanese. There have been African American, Asian, and Polynesian contestants that I can remember. I recall Vanessa Williams being crowned the first black Miss America...and then losing that crown because some nude pictures were discovered...and then going on to have a successful recording and TV career.
As far as how they're "made up" to all look the same....

They're all pretty women...with makeup on. If there are any similarities in their hair and makeup, I'm sure it's reflective of trends in the industry.