Horses didn't cause raiding. Horses were domesticated on the Eurasian Steppe around 3000 BC, but people in conflict, including hit-and-run raids, are known from around the world and long before then, including in the Americas where no riding animals were known until the Columbian exchange.

Horses didn't cause cavalry, horses were domesticated and bred with their modern properties because people wanted cavalry. The tool reflects the creator.