Do you even know what you're talking about? This isn't even a race issue. This is a toxic masculinity issue. A man who could not handle rejection from a women decided to go on a killing spree. He couldn't talk to his male friends about his emotions/feelings before, because of society's hyper masculinity.
However, BLM activists all over Twitter are actually the first ones to address this issue, condemning this black man. So you must have not tried hard enough to find BLM activists' responses to this.

Finally, BLM activists care about crime within their own communities, BUT IT IS NOT A RACE ISSUE ("black-on-black crime" is a myth). BLM specifically looks at systemic racism, police brutality, etc. which are race issues.