That includes game disks that most people sell at yard sales
It does not. "resell" is not a clear wording, since it can mean two different things with software and licenses.
You cannot buy a software and sell copies of it. But you can sell your copy as an used item. And depending on your jurisdiction you also can sell your license, even if the license tells otherwise. There is a reason why big software companies want to call it software license and not treat it like a physical item. They sneak in things in those eula "contracts" to give them "rights", like selling your data, be not responsible and other dubious or illegal things, like forbidding you to give your license to someone else. The parody Southpark did about the Apple license covers the spirit of that.
And they sometimes change the license after the fact. I saw it happen to a game. They changed the license to allow them to collect and sell my data. Now I cannot properly access the game I bought 5 years ago, since I of course do not agree. The "benefits" of drm.
I want to play a game, not sign a contract to do so. I was never asked to agree to an eula on a game on Itch. Things like not buying the right to redistribute when buying a game are regular law, there is no eula needed for that.
and the user just uploads it for free. That's literally pirating
And Itch will remove it. But it needs you to report it. (Insert meme about that fire fighter bear). Might take them a while though.