The best way to argue against liberals is appealing to their feelings and emotions like you would with a woman. If you wanted to make an argument on black crime stating the raw data would make zero impact on a leftist because their reasoning is not objective or fact based but feelings based. You need to restate the argument and imagine that you're talking to a child or a woman and spin it in a sympathetic light. For example, 600 murders a year in Chicago almost all of them black what you would say is NOT "Blacks are more violent" you would say "The black community is losing so many young people to violence something should be done about it". Remember that when you simply throw out numbers to people they just think you're either lying or autistic and revert immediately to NAZI
To add to this the reason they do revert to the NAZI NAZI NAZI screeching is because when a leftist hears something like 53% of all violent crime in the US is committed by blacks it triggers an alarm in their brain that has been programmed in since youth that defaults any blame of black violence and crime to white people. Blacks are victims, they are the product of an evil oppressive society, it's not their fault it's evil whitey etc etc etc. The white guilt overrides any statistical facts no matter how official or accurate. They've been taught in school about how evil white people are and shown in movies the cool black friend, the relatable black rapper, the cool black guy that's just like us that's been pushed for 30+ years by the media.