Yes, the operative word here is ‘in addition.’ Undeniably, jury nullification was used to deny justice to blacks. This action was not in the mainstream of the tradition of jury nullification, and had the tradition never existed, the action of the southern white juries would have been no different than they were under the historical conditions which actually prevailed.
If my memory serves me correctly, they ended up prosecuting the same individuals under Federal civil rights violations when the jury nullified the State indictments. It seems a similar thing happened in the O.J. trial as he was found guilty for wrongful deaths in civil proceedings after the acquittal in the criminal murder trial.
IMHO, things have a way of balancing out. In the example I used of a potential rash of acquittals following a Federal law to prohibit the private ownership of firearms, no doubt there would also be a reaction. In that case however, I believe the offset would have to be much more than a remedy against particular individuals.