Earlier quoted context omitted.
What processing fees? This is a digital platform. It's not like there are dozens of bureaucrats stamping tonnes of papers here.
Instead of being incredulous, assume good faith the other person is speaking with best intent. Try to understand first. There are no free payment transfer mechanisms. Whatever is free is a loss leader. If you don’t know anything about payments, start by reading stripe.com’s documentation to understand how complex this is. Pymnts.com is the industry blog if you want to go deep.
Of course, they don't need to base their threshold on worries about spam/fraud/etc, because they have another hammer for that -> the $99/yr. developer programme.
[1] https://developer.apple.com/help/app-store-connect/reference...