You said this on another comment, it's disingenuous to say that just because it was bad before that it's not bad now. Apple really shouldn't charge 30 percent for doing basically nothing except gate keeping.
If there are only two sellers of mobile apps, you can't just "give your money to someone else" because no one else exists. That's the essence of antitrust, whether it be monopoly, duopoly, or oligopoly. I'd agree with you if there were a free market of device OSes and app stores, but a market of only two is fundamentally unfree.