Again, that's a distraction. Black Lives Matter is focused on the police brutality and the criminal justice system. This is like complaining that Susan G Komen is not focusing on heart disease because their focus is on breast cancer. It is not hypocritical, it is those seeking to distract from the main issue of policing and criminal justice in America. Bringing up abortion is another distraction, why not bring up heart disease or diabetes? This doesn't happen in other discussions, we only see this form of distraction when it comes to those calling out police misconduct.
The "what about black-on-black crime" group does not care about the topic they're bringing up, else they'd see there is already focus on the very topic they claim is being ignored. Black Lives Matter is not mutually exclusive from other causes, there are many organizations focused on crime in Black communities. Nonetheless, the main issue is that when a black person murders another black person, we can be assured that the alleged crime will be prosecuted and punished accordingly, this is not the case with police violence.