Banks are kind of shitty here - if you use another bank’s ATM, your bank (or the other, or sometimes both) will charge a small fee. Usually it’s something like $3, but some smaller banks and credit unions will actually pay all of those fees back, so a lot of folks don’t even notice that it’s there.
This specific situation is weird because it’s a dispensary, though. Thanks to the vagaries of local legality and federal illegality, the dispensaries are totally good selling drugs, but the banks are very much not good openly handling the payments for those drugs. Because of this, most dispensaries will contract their debit payments through a payment processor that can register their card readers as “cashless ATMs,” and who will effectively launder all of their debit transactions. The end result of this is that while the customer can pay with a card like a normal store, they end up having to choose between paying the ATM fee at the ATM, or at the register.