TES is heavily influenced by Roman culture, so we can safely use the original Roman definition of the word "barbaric". And that definition clearly points to the peoples of central and northern Europe, which are most similar to NORDS.
No, Imperials are slightly influenced by Roman culture. And apparently barbaric for Romans meant foreign and different, and if that's the case, orcs are equally barbaric if not moreso.
EDIT: And if you are to go by the barbarian archetype which was portrayed by Romans, that is neither accurate to Norse people or Nords, it actually fits more with orcs. Barbarians were portrayed as savage and uncivilised, and for this reason, people are thinking nords are like that, when they are not. They have a strong society, whereas the orcs are barbaric and uncivilised.