He always had the option of using a donate option instead of locking it behind a paywall. CDPR tried getting him to go that route and he basically told them to pound sand so here we are.

Property rights get all sorts of goofy when money is involved. If homey had released the mod for free and just had a patreon or whatev on the side, no one would care, but because he was charging for it, CDPR is obigated to vigorously defend their copyright.

There's a legal aspect where if you don't defend your intellectual property you may lose it.

You also don't want to set a precedent because if you let some rando do it, why not let a company do it? Why not let Google do it?

Modding implies toying with someone's IP, and the basic premise is that you can't paywall the resulting product. There's a lot of leeway and you can ask for donations, offer private beta to your patrons etc... it can definitely be cash-flow positive but a straight up paywall is a violation of the social contract that governs the modding scene.