Reindeer emerged as a distinct species about a million years ago (Yep, I had to look it up... I’m not a reindeer expert!). The cyclone defense probably worked great against their main enemies (bears, wolves, saber-tooth tigers(?)) for much of that time. When man came along, the reindeer just kept doing what worked well against all the other predators.
Yep, trying to run away from a wolf pack always ended up with the slowest of the herd getting caught and killed. So they continued the same technique not realizing that they could easily run away from the vikings unless they were on their snowmobiles.....