It is kinda understandable from a non-video gamer point of view of the stereotype issue. There were tests done before of people feeling very uncomfortable at the beginning cut scenes that one alone white guy walking in a town with very human looking but “dangerous” looking blacks (more so then the people of the rural town in Spain). Granted in America race regardless of how from we come, has a history of negatively stereotyping minorities that just don't easily wash away and the scene of a mob of black “savagely” attacking one white guy to a person unfamiliar to the RE series would have raised some eyebrows (think when your mother walks in on you and her eyes gape open from the cutscenes).
That said Capcom developed the new partner system with an African agent to side with. Note, Capcom has not, in the past game history, ever really have a seriously decent character of African decent (Balrog? Mike Tyson-parody thug, Elena? Storm of the x-men including white hair and blue eyes, DJ? Jamaican with the HUGE toothy grin, and Dudley? British boxer with the gentlemen rules of boxer acting largely upper-crust) Only four characters in the Street Fighter history yet never on the same level like Ken, Ryu, Guile, Chun-Li, Cammy and Sakura. So it was cool that Capcom realized the reaction from the beginning cutscene showing and retooled the ethnic makeup of the infected (for a while, Africa has a minority of India, Asian and White that's not really expressed upon, not only just black people; seriously with apartheid in Africa for some many years, there are some other ethnic people there outside of just the local residents) and included the new special agent in that region (more of in active role then Luis in RE4, liked him, wish I could have played as him, too bad he died, guess that's why the racism level was not as high, place a character of the area to side with the hero), hope Capcom doesn't kill her off otherwise I'll be pissed.
If anyone ever watch The Bookdocks, and after watching the initial opening of RE5, a couple of my friends and I joked that the character Uncle Ruckus would go out and buy a 360 and RE5 just to play the white guy shooting a bunch of “African Hooligans”.