I think that this is a bit of a joke really, and representative of the over-sensitivity so abundant in America today.
The ad obviously depicts the woman as a jealous girlfriend/wife, which has absolutely nothing to do with race. However, because this is America, and because Americans like their drama, race is instantly brought into this. If it had been a white girlfriend accidentally knocking out another white woman, absolutely nothing would have come of it. However, because this ad dares to use people of another race, it is immediately considered racist and reprehensible.
Race is going to be an issue as long as people keep seeing it, talking about it and even just bringing it up. The congresswoman, while her intentions may have been good, is just emphasizing a (in this particular case, non-existent) difference, and not doing her cause any good.
TL;DR: What. The. Fuck. Why bring race into this at all? Is the congresswoman trying to imply that there aren't jealous girlfriends who happen to be black? Is she trying to imply that while there might be, portraying them in a role no one would think twice to see a white person in is wrong?
/sigh
Only in America, right?