TO BPT:
The call in radio caller actually paraphrased a Maharal, who says that beis din shel mata cannot take into account any teshuvah or improvements made by the perpetrator. They punish based on the evidence and they are not in the business of rewarding good behavior. Only beis din shel maala accepts teshuva and tikkun haneshama. So there is no inconsistency with demanding the highest punishment and yet giving him a chance to do teshuva in beis din shel maala.
The Rambam says some aveiros aren’t forgiven with teshuva alone but require other tikunim, such as yesurim or even death. Again, we can hold out hope that he does do teshuvah but that does not mitigate whatever else may be necessary for his neshama.