I don't blame them either. The difference is that they don't have the low SES kids, which eliminates 42% (state average) of what a public school would have. 24% of low SES kids participate in athletics and 32% of those participate in more than 1 sport. If 2 schools have 150 kids 9-11, privates have 150 non-SES kids, while a public school would have 87. The problem is, they would both be playing in the same class, but the playing field isn't level.
Along with that, privates also don't have to count all of their kids because of how scholarship and non-scholarship kids are counting. Getting in transfers in a public school would make their BEDS count go up, which would move them up a class. That's all people are asking for, to have the private schools play up a class or use a multiplier to bump up their BEDS to level the playing field, in terms of enrollment.