Well, it's the connotation. "Tribe," as opposed to "nation," implies alleged primitivity, at least in my mind. E.g. civilized Romans vs. barbaric German tribes.
Maybe I'm full of shit.
--- On Sun, 9/7/08, John Thornton <jthorn65 at sbcglobal.net> wrote:
> I've never known an NDN who felt the term tribe had any
> negative
> connotation.
> Do you know non-tribal people who have a negative view of
> the term?
>
> John Thornton