Well, I can't think of any other reason.
The man was challenged as a sitting President in the primaries by Ted Kennedy FFS. "Greatest Presidents" of any sort are not seriously challenged in the primaries when they are running for re-election.
I'm not sure what your saying?
I've just expressed why I would have to question why Carter would be considered as such. Maybe the poll was skewed with people who don't know politics or protocol.
I will comend the man for Habitat for Humainity...that's it.