Earlier quoted context omitted.
Especially that they keep the 30% if someone refunds your app. If it would be 15% or less okay, but 30% and keep the proceeds? Seems to be sort of straddling the legality line.
Apple Does not refund the fee? That's insane! On top of that I need to pay apple $100 per year to keep my app in the store. Even PayPal has been refunding the transaction fees (at least until recently).
Steam does not refund the 30%.