When someone comes to your store and says "I made the streets and regulate the power, water supply, sewer, and everything else in this place, cut me 30% of your revenue in taxes" that's the government.
And you'd do well to not confuse those so haphazardly. Apple didn't come to your app and with no cause blackmail you to get your money. They created an ecosystem that did not exist before, and they have to maintain it. Paying for it is completely rational.