I can't speak to the parent's reasons, but I do know that Ohio and Michigan are rivals for a variety of reasons, one from the early indoctrination of their public universities (Ohio State Buckeyes and Michigan Wolverines) into the general populace, even those that never attend either. Those two states have an allegiance/pride instilled into their citizens early that most places don't (apart from maybe Texas and NYC). Some of my friends that I went to college with that grew up in Michigan actually rooted for the Wolverines to beat us haha.