LOL what sophistry!
If every school operates by the same rules, wouldn't they all wind up the same?
If schools are permitted to have different rules, they will be different, and parents will have a choice in how their children will be educated. There will be diversity in the educational environments available. I, for one, am all for choices and diversity in education.
Take another example... It used to be that men's clubs were common throughout the land. Men met and did what men do. They were smoky, dark, ill-mannered and belching was permitted... yeah, even encouraged. Then, in the name of expanding diversity, women were admitted, and the character of these clubs changed or the ceased to exist altogether. Part of our culture was lost. Something different was homogenized, all in the name of diversity.