While I'm inclined to agree with the spirit of your argument, I believe Apple makes the argument that their payment gateway enforcement is in fact in line with that “does this harm a human who does not consent” test.

The argument goes, if I'm not mistaken, that by enforcing their payment gateway, they're assuring that users aren't handing over credit card info and other PPI in an insecure manner.

Whether you buy that or not is up to you, but this is definitely a defence I've heard.