I've dealt with a number of these patients and there is definitely a difference with the attitude among these people compared to patients with insurance and even with people using manufacturer coupons.
We do deal with manufacturer coupons too... most often having the tell people the bad news when their co-pay isn't the "YOUR CO-PAY COULD BE AS LITTLE AS $20 A MONTH*" that's plastered all over the front of the card... with that little asterisk explaining that it all depends on the patient's insurance. "My doctor gave me this manufacturer coupon," they will say, with hope that it will in fact work and give them a discount on their med. They're hopeful, but they don't act like jerks.
It doesn't help the situation when they're told by Doug and his band of miscreants that they're going to "save 75%, 80%, and 90% on most generics" when that's clearly not the case. No, I think the attitude comes from GoodRx telling people that Big Pharma is greedy, greedy, greedy, and pharmacies are lumped into that whole scenario. We're the bad guys, so when the price doesn't match the printed "coupon" we're just trying to screw them with our greed. Bad pharmacist. Bad.
There's also this optimistic notion out there that there really is a Santa Claus... that getting medication at a discounted price really has no trade off. It's just "good-hearted Doug" making an awesome deal in your behalf and giving you something for nothing. People want so much to believe this that they do believe it, and anyone that stands in their way gets the attitude... that most often being the tech or pharmacist doing battle with these damn discounts on a daily basis.