A good ethicist & communicator will probably be able to embarrass you if you're doing something wrong, but so will a comedian. I don't think OP is claiming tha

A good ethicist & communicator will probably be able to embarrass you if you're doing something wrong, but so will a comedian. I don't think OP is claiming that there ethicists have no skill, but rather that it's fundamentally a lot more difficult to evaluate.