just give me my sht
Actually it's more spectacularly stupid design than merely asshole design.
Risking losing potential customers at the last step of the customer acquisition pipeline is incredibly idiotic - from the beginning of said pipeline (for example, an advert being shown to a person) until the end (the customer actually pays for something they bought) there's can be a ridiculous percentage of potential customer which drop of (something like 99.9%+ if it starts at "show advert")
As for somebody that's confronted with this at a checkout, just drop that shopping cart and go somewhere else (also valid in real life when you're at the till and they do something shitty - just drop it and walk away) since that's literally the point were shunning that store does them the most damage.