The problem is that the term is not always (rarely?) used properly. It has become much the same as the term "RINO" in that it's now a rather generic epithet, thrown around for precisely the reasons I and others have pointed out: The two parts evoke negative associations.
"Neo-" hearkens back to "Neo-Nazi", easily the most common political use of the "Neo" prefix prior to "Neo-con".
"Con" conjures up "Con-man" and "Ex-con". Nobody uses "con" to mean "conservative".
That the term was coined by the original "Neo-cons" themselves is, unfortunately, beside the point. It now has a very diluted meaning, is used by different people and for entirely different reasons than when its life began.
A superb post.
Prepare to be called willfully ignorant for refusing to parrot the “official” definition.