Whats really the reason for charging an astronomical amount to pay with CC?

I honestly do not believe that this is all about the fees. This is a huge company so I know you are not paying the top 3.5& that small companies do because you would get a discount for the amount of transactions you get. Why would you not just offer your customers at cost for the transactions. Maybe its my ignorance but my calculations dont even come close to what you are charging if we dont use our bank accounts or debit cards. I honestly think this has nothing to do with the cost but knowing people have been using certain credit cards that will insure their phones for free instead of using T-Mobile insurance. Upper management is making a very poor decision on this manner because I would have accepted to pay the cost of the transaction which is not $14 which you want to charge me if I use a credit card.