Even if they did, it just means that the burden of the extra money is on the rental place instead of the end user.
That's not what this means. I don't support the fee, but the reason for having to pay to play a used game is because it means that they (the publisher or MS) lose out of a "new" game purchase. Used game purchase = no money to anyone other than the person selling it. The fee is so that way the publisher or MS (whomever it goes to) gets a cut of that transaction. Renting a game is completely different; the publisher or MS ALREADY gets a cut from game rentals because they have business contracts in place with rental outfits. There would be no point in assessing a fee on top of that to rent a game that MS already agreed that people can rent.
can you name me just one thing that you have to pay for a second time when you buy it used?
Sales tax. State and local governments in the US, for one, will always (or should I say, are legally entitled to) take their cut of a used-item sale regardless of whether tax has been paid on that item before (i.e., sales tax when buying a used car; the original new car purchase already had sales tax paid on it the first time, so why impose sales tax on the same item again?).