You are misunderstanding, the suggestion is to do it yourself instead of using patreon.

Meta:

So the negative point value, currently -1, tells me that I am asking a rhetorical question and I should have said that I'm asking a rhetorical question.

Back on topic:

I am an expert on in-app purchases circa 2020 and do know that there's no working around it unless you have a deal with Apple. Used to be my job.

Paypal or any other financial transaction entity Is all the same to Apple, the user is sending their money while using an apple hosted app, and apple wants to make sure that users don't get fleeced! So Apple taxes those transactions ostensibly to provide oversight Services.

So the only way for patreon to get around this is to not mention in their app that you can also sign up on you know patreon.com To give money, and to allow users who have signed up and sent money on patreon.com to use the iOS app.

think p2p transactions are exempt - apple doesn’t get 30% of my venmo or zelle.

no clue why patreon doesn’t count though

It's not p2p. 2 transactions happen: you pay patreon, patreon pays them.

likewise with venmo, no? who gets to decide what constitutes a transaction

If we're being honest, private backroom deals based on a variety of business factors and debates. Venmo is Paypal, Paypal has Musk's and Thiel's deep pockets. They can and will settle something.

There is no real line, just imaginary ones apple draws arbitrarily.

As long as you're not using the paypal app on an apple device

It seems this bypasses both Patreon and Apple.