People often confuse interpersonal racism for systemic racism. A Black cop is more likely to go to jail for murdering an innocent Black man, than a white cop would be. Convicting these cops may be fair, but it is not a reduction in systemic racism.
This is Black cops becoming agents of white supremacy, and then being held accountable because they're not shielded by that same hate.
We can hold the Black cops accountable, but not the system that they work in.