I agree that in most cases, morays (even without aggression) can be very dangerous. The temperament of a Zebra eel does allow a careful person to feed it without an accidental bite. The real issue however, is the inability of a Zebra to do any damage, even if a bite occurs. Its teeth are totally blunt and an eel of this size does not have overly powerful jaws. I have been bitten- no damage, didn't even hurt.
My point is, there is no risk being taken, regardless of preconceptions about Morays.