I do get why people get annoyed when private schools succeed athletically. I do. There are definite advantages that private schools have over many public schools - parent involvement, higher socioeconomic status in many cases, etc.
But there’s no simple answer to make it “fair,” if that’s even the right word. Make the private schools separate from the publics? That’s going to be unworkable, unless you think folks will enjoy Dowling vs Des Moines Christian (and if your answer to that is, “I don’t care, that’s the private schools’ problem” nothing I can say will change your mind). A blanket modifier for all private schools? Unless Dowling gets to crown themselves undefeated champions as the only 5A team in the state all year, that won’t solve things. Plus a modifier like that used in Illinois is expressly designed to hinder schools that don’t have fixed attendance boundaries. Guess what - with open enrollment, that’s EVERY school district in Iowa, public and private.
And as I’ve said in another thread, this isn’t simply an issue of public vs private. When you have schools like Waukee or Johnston or Ankeny Centennial or Valley dominating the Des Moines urban schools, futzing around with where Dowling or Assumption or Regina gets classified doesn’t fix that. There are serious, complicated issues at play that affect the participation and success differences between schools, and it will take serious, complicated discussions if we want to fix them.