First of all, it's already been established that this isn't the case of a white man forcing himself on a black woman, it's two people being sexually assaulted by a third party.
Given that the actor playing Parmen (Liam Sullivan) was white, it would be fair to say that Uhura a black woman was being assaulted by a white man. Parmen was forcing himself upon Uhura by proxy.
She just wasn't being assaulted by Kirk.
That's fair, but it doesn't really take away from my central point.
Also, the context of the seen makes Parmen's race fairly irrelevant. They never showed any racial motivations on his part, and given that he wasn't even from Earth, it's pretty clear that there wasn't any. Especially if you consider that he did the exact same thing with Chapel and Spock.