It's what you said, twice.
You made a similar point before about more white arrests ending in use of force - your narrative is that more crime should be reflected in more arrests, that more force means more aggressive criminals. And yet, for BLM folks, more crime or more violence would instead mean racist cops.
If your position is unfalsifiable using data, it's also unsupportable using data. If any possible statistic supports your position, then none of them do.
Letr me try it one last time, hopefully in words simple enough for you to understand:
The report states that police in general uses force against black people 2.5 times as often than against non-black people. If only black and white people are consindered, it is even 3.6 times as often.
When it comes to arrests, force against black people is used 1.3 times as often (the 30% figure "when controlled for arrests").
Some people like to claim that black people are more criminal, more aggressive, etc. in general, and thus those numbers.
If that 2.5 resp. 3.6 number would not be due to racism and such, the only explanation would be that it is because black people are indeed more agressive, criminal, etc.
However, if that were the case, one would also expect a similar number when it comes to use of force in arrests. That is, one would expect the number of police force used during arrests of black people track the number of police force against blacks in general more closely. But that number is much smaller.
Furthermore, it stands to reason that, given that black people face police using force against them 2.5 (3.6) times as often compared to non blacks (white people), that some arrests out of the pool where 30% more force is used against black people is due to the encounter starting with unnecessary force against them in the first place.
After all, it really isn't news anymore that black people get arrested at a higher rate for the same crimes/behaviour than white people, are sentenced more often than white people for the same stuff, often get longer sentences than white people (again, for the same stuff). This means that white people are beeing let off the hook by police/justice system more often than black people, for the same incidents.
But my main point is that the 2.5 (3.6) number of force by police against black people in general vs. the 1.3 number of force against black people at arrests are a discrepancy that can only be explained by racism/racist biases by the police. Or do you really want to make us belileve that black people, if one would grant the claim that they are more agressive/criminal/etc. instead of racist causes being at play, suddenly become much more tame when they are arrested? That would be really silly.
Greetings,
Chris