(Not a lawyer, and someone who is feel free to correct any misstatements) Something that seems to be misunderstood about this is that is was not a trial. He plead, and this was a sentencing hearing. Part of his plea deal was to allow victims beyond the ones in this specific case to read their statements (the alternative, to my limited understanding, would probably have been trials for 100+ victims). The judge herself said in her statements that she was fully prepared for this to go to trial and to act impartially, but he chose to plead instead, admitting to the horrific acts and then compounding it with that letter, which made it clear he had no understanding or remorse. She was somewhat more dramatic than might be the usual, but given that he took a guilty plea, it was not out of line.