This reminds me of gamers who hate the Epic Games Store with passion even though they give the actual devs of the games a bigger cut.
Competition is always good for the consumers. And I get the security part when it comes to Apple BUT it does not justify that they take a cut of 30% from every dev, its basically a money printing machine they do not deserve AT ALL. The same for Valve, they only take 30% because they can, not because they provide any value for it. All the do it provide some servers for distribution and a discussion forum, that hardy costs 30% of a games profits.