"Whatever is not worth doing, is not worth doing well."

Good one.  Reminds me of an old witticism by George Will, on the supposed superiority of aluminum baseball bats:  "Longevity is no virtue in something that shouldn't exist in the first place."

That said, your statement that "Jesus' 'living presence'  . . . is so amorphous as to be . . . the inspiration for . . . incredible harm" is unprovable, and thus, by your own lights, not worth much.  Jesus, even just reasonably well understood, is goodness itself, and therefore, cannot be the inspiration of evil.