According to some posters, blacks, etc. cannot be racist.
I have heard some people make that assertion, and there are certainly people ignorant enough to believe that statement at face value. However. when some people espouse those ideas, context is everything. (and perhaps it's their fault for not explaining themselves correctly).
When I challenge them on that assertion, and demanding that they quantify their statements, I find what they're actually referring to is the systemic effects of racism with regard to disproportionately negative effects as a result of the racism.
To elaborate, there's no doubt that there are some whites who hate black people, and vice versa.
However, whites aren't very likely to suffer as a result of a black person hating them simply for being white. However, the same isn't necessarily true when it's going in the other direction.
For example, I've never heard of a white person being denied an apartment lease because the landlord was black and "wanted to keep a certain element out of the community". I've never heard of a white person being harassed by cops for "not being in the right neighborhood". You've never heard of "black flight" where a white person moves into a black neighborhood, and all of the well-to-do black folks in that neighborhood, fold up shop and move their residence and businesses somewhere else to get away from the "white element". (As the old Chris Rock joke goes "here comes the neighborhood") However, White Flight was most definitely something that occurred. You didn't hear of black leaders in the 50's & 60's purposely raising property taxes on white families just so they would lose their homes, and then turn around and sell the properties other black families for cheap, and then drop the property taxes back down once all of "those people" were gone.
So long story short (I know, a bit late for that after my ramblings above), when some people are saying things like that, what they actually mean is that whites hating blacks is more likely to have a real negative impact on the black community as where blacks hating whites is unlikely to have any systemic impact on us at all.