A kind of similar funny example is in Xenophon's Anabasis, where he mentions "millet-eating Thracians", which always cracks me up. Lots of people ate millet, including Greeks, but this group got referred to as millet-eaters. Seems hilarious to me.

"When all of them had been prevailed upon, they continued the march with Seuthes, and, keeping the Pontus upon the right through the country of the millet-eating Thracians, as they are called, arrived at Salmydessus."

https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1...