I don’t think it’s really intended for KYC/AML/ATF to keep poor people out of the system, though it is true that in practice they mean it’s hard to have access to the financial system if eg you’re homeless or your name is Mohammed and you send remittances to your family abroad. And banks have a shared ‘blacklist’ of people who cause them compliance pains so those people who have a hard time at one bank can end up having a hard time at many other banks.