It's worth noting that getting to "23x" here requires taking the ~5x baseline figure and then multiplying by five AGAIN, because there are only 1/5 as many Black potential perps as white potential perps. 

But, there's a 3rd step, if you're going to do that - you next have to DIVIDE by five, because there are 5x as many white potential targets. I.e., a totally anti-racist criminal would find that he robbed 5x as many white people as Blacks. This gets you back to, basically, baseline. 

To me, the more notable thing here is that there are 20,000 US murders annually, and about 550 are B/W inter-racial, if we accept these figures as accurate.