That isn’t what a DMCA is for. Someone being compensated for the work they’ve done is unrelated to suing a company for using your art/code/work without permission or reference. Weirdly aggressive to modders though.

Edit: for your edit, you can’t monetise a mod for someone’s else’s game directly but you can absolutely make money modding. And even if their EULA enables them to do so, taking a modders code without at least a reference is pretty dogshit. Literally a million dollar studio ripping off people who did it out of passion knowing full well they wouldn’t get compensated. I’m surprised a EULA can protect them legally for doing it tbh.