No, I believe injustice anywhere is injustice everywhere. Also, I agree with you the injustice is worse when committed by people in positions of authority acting in that official capacity.
That said I don't condemn everyone based on the acts of one or some, that goes for police and BLM.
>And isn't the fact that these bad acts are persistent—regardless of frequency relative to good acts—at the very least suggestive of systemic issues?
Yes, part of why I am happy about the proliferation of video and want to shine a light on the nameless, faceless prosecutors making decisions behind the scenes to sweep these tragedies under the rug to protect the officers. Again no one talks about it, no one knows the name of the prosecutor who initially watched the video and refused to bring the charges against George Floyd's murder(s), that helps fuel the systemic issues. Video will help with accountability, but that is only helpful for what happens on the streets, we need to also focus on behind the scenes on the nameless, faceless people protecting bad actors.