Mississippi Masala shows a different angle on race relations in the US beyond black and white. This is made pretty clear by the scarce presence of White characters. The only time Whites seem to appear is to cause trouble for both the Indian and Black characters: e.g. the banker who threatens to repossess Demetrius' van, the guy who yells at Demetrius at the beginning of the movie, the party kids in the motel, and the guy who tries to hustle Meena's father for money. The film's focus, rather, is on the Indians and Blacks in Mississippi.
However, I don't feel that the film accomplished this all that well either. As someone mentioned earlier, the communal frustration over Meena's and Demetrius' relationship seems to come out of nowhere. Meena seems to fit in pretty well when she is dancing at the club. She is also welcomed by Demetrius' family when they eat dinner together. The film doesn't quite explain why people are suddenly so torn over their relationship. However, I think the film does a pretty good job of raising the question of who belongs where. Meena and her family had to leave because they did not "belong" in Uganda, and they are not really welcomed by the Whites in the movie either. And yet, they are not accepted by the Black community, even if she was born in Africa. So where does one belong if not even in the place where he/she grows up?
This sense of belonging, I think, is the common thread between this film, BLT, and Monkey Dance. Upper middle class or working class, intelligent or not intelligent, the kids are all struggling to make their own way in a new world.