Same reason why Valley City, St. Marys, Shanley, Beulah, Wahpeton, and so forth were "too small" to compete with the AAA schools in football. So they move down and manhandle every AA team. Gee, that's fair to those teams that are legitimately small towns.
All about winning by having every advantage possible. Upsets be damned.
Now the bottom AA teams should say they are too small to compete with VC and Shanley and then go beat the hell out of A teams. And trickle it on down...