I've walked past more than one anti gang protest/demonstration just going about my day in the City. Wether they were with BLM or not I dunno, but I can say they were all black.
And yeah, multi tasking is a thing, multiple groups of people doing different things is also a thing. People can protest gang violence and police shootings. Wether it's the same people doing both or two groups of people doing one or the other. That is, in fact, what already happens.
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