It seems to me that if a person referrs to another person as a moron or other names, they are opening the door to talk about themselves personally. Lets face it, 'calling' someone a moron is personally attacking their credibility and their mental capacity, not to mention the fact that it an outright insult to mentally handicapped people.

Moron \Mo"ron\ (m[=o]"r[o^]n), n. [Gr. mw^ros foolish, stupid.]
1. (Pedagogy) A mentally retarded person whose intellectual
development proceeds normally up to about the eighth year
of age and is then arrested so that there is little or no
further development; an adult having the mental
development of an 8-to-12-year old. A moron is considered
capable of doing routine work under supervision.
[Webster 1913 Suppl. +PJC]

So use such terms at your own peril, because I will call anyone on that anytime I choose. Period!!