I figure it is simply because the leftists ascribe all evils to white people, the patriarchy, Christianity, capitalism, and Western Civilization... and when criminals run amok, it is not really their fault, it is the fault of the filthy white Christian men. It is unjust to punish murderers, rapists, robbers etc... who really needs punishment is western civilization in general, and white Christian men in particular.
Am I off base here?