Of course.  But that isn't the relevant statistic, any more than is the fact that blacks are much more likely to be killed by blacks than by whites.  (About 93% of murdered blacks are killed by blacks.)  The numbers you cite are mainly a function of that fact.  Whites are usually among whites, blacks are usually among blacks.  The stat you cite does not undermine the fact that though black men are only 20% of the population, they commit at least 40% of the total number of murders, which is far out of proportion to their numbers.  I certainly would not chalk this up to skin color or race.