A corporation cannot be communist, because it has no rule of law over its users. Product platforms are not governments, they're not countries, and there is no expectation of public access. The "communist" argument is completely irrelevant.
Think of iOS hardware and software as a giant amusement park. I'm going with Disney World, because it's familiar.
Disney allows plenty of third-party corporations inside its parks. Various rides are "sponsored by" third-party corporations, and those corporations are heavily involved in the process of making these rides happen. However, Disney corporation has final say on what goes. End of story.
Apple views the iOS ecosystem like an amusement park in which they are the curator. They open the doors and allow third-parties in, but they hold unilateral decision making power over the user's experience while at the park.
Maybe you're not in to amusement parks. I certainly get that, but there are other options. No one is forcing anyone to sign up for the Appleland trip. It just so happens that consumers really like the curated experience, so if you want in on the action, you have to understand what you're getting in to on the way in the door.