“ cannot be told of their right to nullify during the trial, a narrow right to nullification exists…”
There is no such right, Jury nullification is simply refusing to follow the law.
If you are called for jury duty and don’t believe in the law in question, say so to the judge. You’ll be excused. If enough people do that, pressure will be on to change the law and/or to free the defendant.
If you go the cowardly route and refuse to deliberate in good faith, what will happen is that judges will start dismissing recalcitrant jurors and seating alternates.
I don’t buy your claim that blacks are treated unfairly by the judicial system. If you look at the violent crime rates by race, the prison population by race looks roughly proportional. And when you look at sentencing, consider that before someone actually goes to prison, they’ve been through one or more diversion programs and probation. Compare the prior records of criminal defendants by race and get back to us.