> It is wortthwhile to look up "moral error theory" in wikipedia.
While it's true that many individuals can find no objective grounds in their experience for belief in objective ethical principles, e.g. can find no objective grounds in their own experience for judging the relation between Beatrice and Benedict in Much Ado About Nothing objectively better than the relation of a baby murdering psychopath to babies, this doesn't demonstrate that there are no such grounds.
What the Bedlamite implication demonstrates is the psychopathology of the individuals in question, a psychopathology also demonstrated by mistaken identification of "reason" with axiomatic deductive reasoning and a linked immunity to a reductio ad absurdum argument.
Ted