Yeah, if this is true, then it isn't racism, good or otherwise, just a statement of fact. The question is, is the fact that they're black the most useful thing to be having a national conversation about?

How about "people who are POOR are more prone to committing violent assaults on subways..."

Or "people who have MENTAL HEALTH issues are more prone to committing violent assaults on subways..."

Or perhaps "people who are UNEMPLOYED are more prone to committing violent assaults on subways..."

These are all much more likely to be relevant, and more importantly, solvable than the colour of somebody's skin. It might even spark a conversation about whether black people are more likely to suffer from these problems and why that might be.

The point is, the factor that you initially hone in on is important. Skin colour is unlikely to be a useful one when you think about it.