What IS good, and how do we determine it?

[abaris]

There was a rebellion.
Some of Charlemagne's homies were killed in the uprising.
Charlemagne exacted revenge.

I'm not convinced the comparison to the Japanese army is justified, but if you say so...

The comparison is valid. First, if Charlemagne hadn't conquered the Saxons there would have been no need for rebellions. The Saxons didn't ask for him to invade in 772 and to destroy their holy sites. I'm not going as far as to say, spreading the word was the major reason, but it was a reason. Nearly 30 years of constant war ensued, by all accounts as brutal as the 30 years war some 800 years later.

What you say is purely a revisionist standpoint.