I disagree that your question is the only important one to answer on this topic. Among other things, the study authors are seemingly trying to answer the question if more racial diversity among police would reduce the amount of shootings:
> Because racial disparities in FOIS do not vary based on officer race, hiring more diverse officers may not reduce racial disparities in FOIS. This is not to say that increasing officer diversity is without merit, as increasing officer diversity may broaden understanding of diverse communities and increase trust in law enforcement. However, these data suggest that increasing racial diversity would not meaningfully reduce racial disparity in fatal shootings
There was an NYT article quite a few years ago examining the topic of racial disparity in police departments(https://www.nytimes.com/interactive/2014/09/03/us/the-race-g...) which contained a short blurb with a similar conclusion:
> “Even if police officers of whatever race enforce the law in relatively the same way, there is a huge image problem with a department that is so out of sync with the racial composition of the local population,”
Here's another article from the washington post on it(https://www.washingtonpost.com/news/storyline/wp/2014/08/22/...):
> Some social scientists have taken a look at the racial disparities in the behavior of officers, but the topic is still being studied. And there is hardly any research at all on whether racial disparities exist between officers when they use force.
...
> From the studies that have been done, however, there’s no conclusive evidence to show that white and black police officers treat suspects differently — if anything, some of the studies show that black officers can be can be harder on black criminal suspects.
Is this an obvious conclusion? I don't think so. It only took a quick google search to find a site campaigning for police reform(https://www.joincampaignzero.org/representation) which contains a study with a different conclusion:
> Moreover, research shows police departments with more black officers are less likely to kill black people.
To me it seems like the topic is still under active research, even if there are already existing tentative conclusions - especially since the conclusions are counter-intuitive, it makes sense that the authors would want to provide more data to the subject.