Ah, it looks like I made a previous explanation. Ah, well.

Explanation: During the Battle of Idistaviso, “[f]rom nine in the morning to nightfall the [Germans] were slaughtered, and ten miles were covered with arms and dead bodies.” In addition, the Roman general, Germanicus, exhorted his legions by saying, in an unusually bloodthirsty statement, that the only resolution of the war would be by the total extermination of the rebellious German tribes.

While I joke and meme a lot about barbarians being ‘civilized’ to death, this is really quite an extraordinary moment of bloodlust. It shows, I think, just how far humans can go in dehumanizing their enemies, as Germanicus was noted for his mercy and generosity - towards his fellow Romans. In his dehumanization of the Germanic tribes, he felt comfortable calling for the deaths of the entire nation.

In the end, the point was moot, as Germanicus returned to Rome in triumph while the rebellious Germanic tribes retreated and dissolved into internal conflict, as they had before their short-lived alliance against the Roman Empire.