Can business purposely make it hard to process a credit card to discriminate?

Among other cards I have a CashApp card, which is marketed towards off the grid type of people, and a Self Credit Card which is based off a deposit you build while building your credit. See where I'm going with this? So my CashApp card I had to replace due to a merchant mismanaging it. When I got the new one a lot of places would reject it on the first two inserts, then all of a sudden that stopped, which doesn't make sense if it was the card. I went to Dunkin a month ago, my CashApp card was rejected, the cashier examined it with his hands, told me to swipe, then said I had to type in the card number. This also happend today with my other card, the Self card. Then low and behold as im trying to enjoy my coffee, 8 other people pay by credit card without having to do that. I think this is some kind of discrimination. My hair was a little messy today but I don't look like I can't have a credit card. I would ask cash app about this but the issue has been resolved. I asked the cashier more about the issue and told him since it happened with two other cards and not other people that it was discrimination. I'm not going to contact Dunkin because I feel bad he was put in this position and they won't do anything. I will go to another Dunkin by me I've been going to where there is no issue. Am I onto something? I attached a pic I took today.