I'm definitely angry about the situation. I made a thread about it earlier, and it appears that GTA V on Steam is getting hit hard with negative reviews.
That said, there's certainly a grey area concerning mods, but because most publishers have turned a blind eye to it, malicious content can go unpunished. Now, I'm not suggesting that publishers should be selling mods at all (We all know how that went down with Bethesda), but I am suggesting that maybe mods need to be officially supported. As an example, I play Cities: Skylines on Steam with officially sanctioned mods using the Steam Workshop, all for FREE. Some are scripts, assets, textures, etc. That's a policy I'd like to see embraced by more publishers.
Personally, I've only modded GTA V textures for clothing and vehicles, but will I continue to support modding under any circumstances.