It's the imagery as it related to American depictions of blackness. Apparently there's a scene where a gang of black men attack a white woman? In any context, that image is going to be charged with racial overtones.
That does happen but they're not really attacking her, they're forcing her to take a parasite and become a zombie. You're then forced to kill all of them.
Actually I'm pretty sure the same thing happens a little bit earlier with a black man being forced to become a zombie.
Both of those actually happen really early in the game (I think the black man might even be the first zombie you fight). To me the scenes weren't really racist at all, they were just showing people getting infected.
Actually I would have to say that one of the most racist things in the game is when you're going through areas of tribal Africans. They wear the stereotypical tribal clothing and attack you with spears while you're mowing them down with guns. However they were infected and I had no problems killing them just like any other zombie.