I think that the flaw (at least as i see it) in NJ's argument is that moral relativists do not have their own personal moralities, that they are amoral.
This position is not only extremely rare; it is also an extremely difficult code to follow. Fact is, we are human, and with that comes a bit of emotional, cultural, and likely even evolutionary baggage. This has significant influence on the way we live our lives. We are not mindless and unfeeling.
I'm sure, however, that some are able to put aside their "humanity" and follow such a path, but not many.
ABE: i don't expect all scientists are moral relativists either.
Edited by U can call me Cookie, : No reason given.
"The good Christian should beware the mathematician and all those who make empty prophecies. The danger already exists that the mathematicians have made a covenant with the devil to darken the spirit and to confine man in the bonds of hell." - St. Augustine