I believe it reflects reality, or is at least a strong approximation of reality.
I think the cause to first order is economics. Second and third order terms with much less but still contributing importance are political (decades of policy failures like the War on Drugs and welfare expansion, for-profit prisons, etc), and cultural (there is far too much celebration of crime culture, gang culture, and respect culture that normalizes the state of things in the black community).
Further down in their comment they cite statistics about variant violent crime rates by race, where African Americans commit more than 50% of violent crime, which seems in line with your cited non-lethal force rates. Violent criminals receiving proportionate rates of violent force doesn't stand out as a disparity.
According to The Washington Post, 19 unarmed black men were killed by police in the entirety of 2019. Black people are disproportionately killed by police for their population, but almost exactly in proportion to the rate of violent crime broken down by race.
Obviously every "unjustified" death, especially deaths by the police (who are trained and held to higher expectations given their position) is a tragedy. The riots and protests led to far more deaths, far more injuries, and far more damage (including causing the second wave as cases were decreasing) than seems at all justified even considering these tragic police shootings.
In other words, while police brutality is a genuine problem, the response was completely disproportionate, misinformed, and morally wrong.
Amazon has stated that it warned Parler for months without redress, but to offer another perspective, the CEO of Parler stated in an interview that they were notified the day before they got the plug pulled, sought to work with AWS on solving the issue, then were "deplatformed" the following day.
He said she said, but obviously both sides are incentivized to make themselves look clean
Serious question: can you show evidence where this has actually taken place in the school curriculum in recent times?
Anybody can advocate for anything, from wanting to teach Satanism and anti-vaxx science to GMOs cause cancer and "New Math", but the curriculum doesn't bend so easily since there are federal standards. Beyond fear mongering and "leftist memes", any real examples?