"Systemic racism of the gaps" is not an argument - the fact that disparities exist does not prove that there are any artificial barriers preventing people from being successful based on their race. The same system which supposedly persecutes against black people simultaneously allows Asians to thrive - they achieve better scores in the education system, have significantly higher median incomes and the lowest incarceration rates. If "the system" is built for the benefit of whites then the white supremacists in charge didn't do a very good job. A disparity between outcomes of black and white people does not prove systemic racism any more than the disparities between asians and whites do.
In terms of policing, year after year studies fail to demonstrate a significant disparity in terms of policing - in they exist at all, it's been demonstrated that black people are (on average) less likely to be shot by police and more likely to face some degree of physical violence compared to white suspects in similar circumstances.
https://www.wsj.com/articles/the-myth-of-systemic-police-racism-11591119883
https://www.nytimes.com/2016/07/12/...police-use-of-force-but-not-in-shootings.html
When you look at the numbers with a cool head, things click together rather neatly. Predominantly black neighbourhoods have higher levels of criminality, and as a consequence there's a higher police presence in them. Where there's a higher police presence there are more encounters with the police, and any encounter with the police can potentially be fatal, regardless of whether you're black, white or neon green.
The problem of criminality needs to be addressed with more policing, not less, as well as better training and a more stringent selection process. Negative interactions with the police aren't just fueled by poor policing though, they're also fueled by a strong distrust of the police which is endemic in those same neighbourhoods.
There are so many causes of this situation that trying to name them all is almost futile - single parenthood (statistically increases the likely hood of incarceration by a significant margin), wide-spread use of drugs, relatively low standards of living, poor educational outcomes, the world is your oyster when it comes to naming and shaming. Some of those problems could perhaps be addressed with policy, others need solutions in the communities themselves. "Whitey's fault" is not a solution, and does not adequately explain the disparities we see either.
One would be a fool not to admit past injustices, but one would also be hard-pressed to point out *systemic* injustices today. There are no laws on the books that explicitly discriminate against black people. There are certainly laws that are aimed to combat specific crimes, however if those crimes happen to be predominantly committed in black neighbourhoods then the logical conclusion isn't "systemic racism", it's "criminality problem".