You answered your own question, it’s not about them getting a cut, if it was Primal would have been banned from doing it also. This was a technical issue. It’s easy (and some think it makes them look cool) to criticize Apple. But they have been consistent.
Also the appstore is proprietary software, they’re responsible for it and the apps on it. And I appreciate having an appstore where I don’t have to worry about malicious apps, like android.