I think this is describing how the system includes momentum, and you're saying that the system (momentum) is producing racially-biased outcomes _without_ racist input today. That's true in the strictest, most technical sense, but is this supposed to be a motivation for reparations or something?
Along those same lines I suppose we also suffer from systemic genocide, systemic famine, systemic war, and every other crappy thing that happened to people in history and were not somehow complete corrected for by a counter redistribution of wealth and status.
The problem with your counterexample ("systemic famine"/"systemic war"/etc.) is that those are one-off events in the past, and thus they don't cumulatively add up and compound to create very unequal outcomes today. A more appropriate hypothetical would be that the last 400 years of one's ancestors all experienced genocide, war, or other similarly "crappy" things.
As for one-off events, it seems like just a matter of degree, not principle. Though surely genocide continue to have negative affects on the victimized group to this day.
Your argument is mostly "whataboutism" - you point out that terrible things have happened to groups of people in the past and those things have inter-generational effects. Of course it's true.
That being said, of course it's a matter of degree, but at that point you're just arguing semantics. Driving your car at 25mph vs 125mph is only a difference of degree, and yet one is totally permissible and the other is incredibly dangerous and would land you with a big fine. The key point here is that speeding becomes increasingly more dangerous as you drive faster, to the point that exceeding speed limits by a given amount becomes reckless driving because you're much more likely to cause injury and/or death to yourself and others. In the same way, racist systems create a compounding disadvantage that is almost impossible to rectify simply by changing the laws to make them "colorblind" in the modern day.