Racism is not a fact of material existence, i.e. an object in the material world we inhabit. It is a state of mind people can have.
Systemic racism is, as I understand it, a society in which race has a significant affect on the life-prospects of people of different races. Those prospects in the present cannot be divorced from history. I feel certain that the U.S. is not the only nation in which systemic racism exists, but it is the only nation of which I am a citizen.
I have no doubt that African Americans can be racist, only not towards European Americans. The essence of racism (as I understand it) is its irrationality: to have an extreme antipathy for members of a given race for no valid reason. African Americans certainly have valid reasons for having an extreme antipathy for European Americans — though very few do, in my experience.
Other than those who have given up on ever being respected, even the most vociferous African Americans have as their goal being respected as human beings by all other people. There is respect that must be earned, but there is also respect that people are due merely by virtue of being fellow humans. That is the respect that African Americans have been systematically denied in this country— beginning with slavery, continuing through Jim Crow, and still with us in the present.
I think of it in terms of a mugging. European Americans are (as a group) the mugger, African Americans (as a group) the victim of a (historical) mugging. It makes sense for the victim to have extreme antipathy for the mugger, but it makes no sense for the mugger the have extreme antipathy for the victim.