Systematic racism = racism+power. Black people in the Western world cannot be systematically racist against White people.
If, hypothetically, the county government in Macon County, Alabama decided to claim all property held by white people (and only white people) as eminent domain, would that not count as an act of black systemic racism? Or must majority demographics be held at some arbitrarily higher level of spatial aggregation in order to count?
You don't have to point to a hypothetical scenario, actually. Zimbabwe under Mugabe actually did something along those lines.