The better approach is to define what inputs are going to be used, explicitly. Some like race and religion are going not going to be used, as discrimination on the basis of race or religion is off limits. But age, past offences, and the like probably are

But I think we're diverging considerably from the original point: that forcing an AI to produce equal outcomes despite unequal behavior in the real world is not the elimination of bias, it's the deliberate introduction of bias. If we have an AI that predicts recidivism rates, and we engineer it to produce equal predicted rates across all groups despite different between rates groups in the real world then we are deliberate introducing bias. The truth, regrettable thought may be, is that a magical AI that operates with 100% accuracy - the only people who it flags would have re-offended - is going to produce disparities because recidivism rates are not equal.