I see your point but disagree with it.
Your rationale says if you are going to play a game make it count win or lose. Seems reasonable except when you consider the circumstance of risking an accrued (note I didn't say earned) win to play a replacement game. The IHSA rationale is that if you aren't going to play a game because the other team forfeits, it's okay to count it as a win, but if you are in this for the kids and succeed in finding an opponent, you risk the bird in the hand. The IHSA is effectively encouraging schools to accept a W they didn't earn over taking a risk that they should be taking.
BTW, it's exhibition, not exposition.