Winco does it because they hate white people. White people use credit cards to earn mileage and other fun free things. Minorities can't afford credit cards. Winco wants to take away fun things from white people.
Stopped for lunch at my favorite Mexican restaraunt. They make the best fresh salsa. It is a small family owned restaraunt. A very pleasant young Mexican lady waited on me, probably the owner's daughter. To make her feel more comfortable, I ordered in my best dockside Spanish. She just stood there with her mouth wide open. The silence lasted too long so I repeated my order. Still no response from the young lady. Then it dawned on me, the Mexican waitress could not speak Spanish. So I said #8 please. And all was well again. Things are very different in Idaho.
My wife had a green card. She had to jump through hoops to get it. Of course that was 40 years ago so, maybe it's changed since then. Side note: When she got her U.S. citizenship, it was a big deal. I remember the people in the court room from all over the world who were so happy that day. We've kept her flag and copy of the Constitution all these years.
They accepted credit cards back when I had my problem with the debit card I used at Winco. I remember as the clerk walked me through the process of using my debit card that he gave me the option of using a credit card. So, it hasn't been always that they haven't accepted credit cards.
Many years ago I attended a citizenship ceremony. We sat in the jury box, possibly as witnesses, but not sure about that. What I do remember is: The judge asked very difficult questions. Both about our gov. system and our history. The joy after the ceremony was contagious. It was a very happy and emotional time for our new citizens.