Well said, my liege.
As we've discussed before (for which read "as I've banged on about endlessly before"), whimsical 21st Century thinking likes to portray certain tribes/peoples - and this definitely includes the Celts - as being peace-loving proto-hippies, in touch with earth energies and part of some Celestial Oneness. Said Celestial Oneness was untimely ripp'd from them by more aggresively masculine and/or technologically advanced cultures such as the Romans.
"Barbarian" derives (I think) from a word just meaning "bearded ones". Although that is not a particularly offensive word, it does give an indication of how the Romans viewed other peoples. I think we can see echoes of that mindset today in the way that some Londoners refer to things outside the capital as being "provincial", which clearly carries negative connotations without actually expressly stating them.
But Urien Gwledig is right. Roman society and Celtic society were both capable of great beauty and great cruelty. Being on the losing side doesn't make one any more morally superior.
Regards,
Peter