Why might a roman historian like ammiamus want to compare the Huns to unthinking animals?

A Roman historian like Ammianus Marcellinus might compare the Huns to unthinking animals to emphasize their perceived barbarism and savagery, contrasting them with the more "civilized" Roman culture. This comparison could serve to dehumanize the Huns, making their violent actions seem more instinctual and less rational, thereby justifying Roman fears and hostilities towards them. Additionally, such imagery would resonate with Roman audiences, reinforcing their cultural superiority and the need for military vigilance against perceived threats.