30% is a reasonable cut for the distribution of software for which almost all revenue is marginal profit. When it’s a transaction for services that cost money to provide (like Uber or online shopping) or a transfer of money on behalf of someone else (think Venmo or PayPal or just a regular banking app), a 30% cut of the whole transaction doesn’t always make sense.
Apple recognizes this and doesn’t take a 30% cut for those types of services. But they don’t always categorize things correctly. Patreon is something like PayPal, whether the app owner takes a a small cut of each transaction, so paying 30% represents a huge cut, like 10x as much as they make.
Apple (and Google and Steam) are taking a software distribution cut for a service that more closely resembles payment processing, which is usually a 1-3% fee, not a 30% fee.