The most alarming part of this is actually the clear evidence that they use arbitrary and inconsistent enforcement of vague rules to actually enforce OTHER secret rules. In this case "no app recommendation engines", or more broadly "nothing that drives downloads".
They didn't just say that. They pretended it was some other rule. Which means what people suspected is true -- they lie to you about the reason for your app being removed. You may have zero chance of complying with the rule they said you violated, because it wasn't really about that rule at all, it was about another secret rule or policy decision.
To me that's far more alarming than the fact that they decided to forbid a class of app that had previously been allowed.
They could arguably defend the ability to forbid any category or type of app they want with no notice; it's their store, they make the rules, they decided that kind of app was unwelcome. Although that they don't simply admit this must mean they think it would make them look bad, and/or discourage developers from developing for their platform, and/or be evidence of antitrust illegality, and/or something.
But when they instead lie about it... it makes the whole sytem into a kafkaesque maze, you never know when they are lying to you about their rules and when they are telling the truth, when there's something you could do to "fix" your app so it would be allowed, and when they have just already decided the whole category your app is in is banned; it's not because you actually accidentally violated any rules, and there's nothing you can do to fix it, but they will instead try to, well, "gaslight" you (I normally am not fond of that phrase, but it seems apt) into thinking you were in violation of a rule.
> He said he thought it was unfair, but this was something Apple set out to do, and even as Senior Director of App Store (person directly in charge of App Review), he could not stop it.
I would like to believe if I were him, I would have had the courage to quit. NOT because it is unfair to the apps banned. But because LYING about it makes the entire App Review process illegitimate and unethical and "gaslighting" developers, and I wouldn't be willing to be the person directly in charge of all App Review if it's gonna be BS like that.