Exxon review: gas price markup for using exxon card

I purchased gas at this station on May 26, 2019. I have been to stations that add an upcharge for using credit cards before, but never a Exxon station that upcharges you for using an Exxon gas card. This is ridiculous. Why should it cost me more to use your company's credit card? I will never purchase gaas at that station again or any other station that does that.