In my experience working in finance and healthcare as a founder, education and cash flow needs box out poor people from conventional banking; they live check to check, public schools in poor areas are below average, et al. Poverty feeds on itself, unfortunately.
KYC/AML ensure our online applicants are who they say they are. It's a very straight forward regulatory requirement to safe guard the movement of money by US citizens and not foreign entities. This is one of many anti-fraud measures we take because fraud is a massive issue and capital loss is exceptionally hard to recover -- especially for internet banks where attacks come from all over. Fraud networks are extremely sophisticated and based on your remark about KYC/AML, I don't get the impression you appreciate the depth of it. It has nothing to do with low-income citizens except to the degree to which social determinants (lack of transportation) may prevent someone from getting their identification renewed, but this is a much bigger issue for that individual than just opening a bank account. Online banking is more accessible for low-income for this reason vs. brick and mortar who avoid branches in those areas.
For a startup or even a crusty old bank looking to improve margin and slim down their back office, services like Alloy make KYC/AML a very simple request/response component within our application. There's really nothing complex about it. I'll take KYC over HIPAA any day of the week.