let me put on a freedomite hat and say: they are a private business and are free to dictate how they do their business regarding bill-settling methods; if a customer doesn't comply they can simply go someplace else

really though, I have never EVER seen a business which would not take cash. sure, I have seen businesses encouraging card payments and there are plenty of reasons to: one is money laundering I mentioned in the previous comment; cash is fucking expensive to handle (where I live it's 0.25% markup on card transactions vs 3 to 5% markup of a cash convoy); cash can be stolen by employees or simply misplaced. I know all this varies in different countries but where I live every single shop has cashless options, even farmers' markets stalls take cards because it costs them close to nothing and they save time and money not gathering cash.

I see it as a way to hurt people without cards or bank accounts

well if a business should accept cash or not make a transaction at all then they are not acting rationally by refusing business. why do you they would intentionally hurt people with no bank accounts?