The latter is probably not his intended meaning given that he states "these days the base rates for violence among blacks is higher."

Those are the words he puts in the mouth of "a rational decision-maker using Bayes Theorem," whose conclusion he identifies as a moral abomination. It is ambiguous whether or not he thinks that belief should pay rent.

I think calling something a "moral abomination" means it directly conflicts with your values, rather than only being a "bad idea."

The purpose of indignation is not to make calculations easier, but to avoid calculations.