No it's not. The modder didn't sell anything. Wanting to be compensated if somebody else makes a profit from your work that you put out for free is not the same thing as selling it.
Wanting money for your work isn't selling?
No, because they weren't even offering it for sale. But they also weren't offering it to be taken to be sold by somebody else for a profit. Which is what the studio did anyway. So now, after the fact, they can either pay a compensation and credit the modder, or they can remove their stuff from the game.
No it's not. The modder didn't sell anything. Wanting to be compensated if somebody else makes a profit from your work that you put out for free is not the same thing as selling it.
Wanting money for your work isn't selling?
No, because they weren't even offering it for sale. But they also weren't offering it to be taken to be sold by somebody else for a profit. Which is what the studio did anyway. So now, after the fact, they can either pay a compensation and credit the modder, or they can remove their stuff from the game.