you could just as well say that the mortgage interest payments the bank takes in are subsidizing credit card points, or HELOC origination fees, or account maintenance fees are subsidizing points. you could also say the bank's profits from trading securities, or their lucrative wealth managements services are subsidizing points. but none of that would be accurate. The banks have a range of services and some are big wins and some are marginal and some may even be losses, and of course the wins help balance out the losses, but unless you can show that points disappear if poor folks manage their credit better and pay more reasonable interest rates, it's not reasonable to frame points as being subsidized by the poor.