Game developers pay manufacturers to license the copyrighted material that they want to reproduce in their game (car designs, car name, logos, etc). For example, Turn10 Studios and their Publisher signed a contract with Ferrari to reproduce their copyrighted cars in Forza games. That relationship involved Turn10 and the Publisher paying hundreds of thousands or million of dollars to Ferrari and in return they were given high resolution 3D files of their cars, liveries, etc. Turn10 also had had to pay the other copyright holders that appear on those cars such as Michelin for the tires, Shell Oil for the Shell logos that appear on the car, etc. In return, Ferrari, Michelin and Shell stipulated in their contract with Turn10 how those cars can appear, how they would perform, and how those logos would be displayed. These contracts cost millions of dollars to create and enforce across a single video game.
Now comes a modder who rips that content off of Forza and gives it away or resells it as his own work. His attitude is that he spent time stealing it from Forza and making it work for Assetto Corsa, and his time is worth something. So he wants to be paid for stealing and converting the work. But just because someone spends a lot of time and hard work stealing doesn't mean it isn't stealing. The theft is clearly a violation of the contract signed between Turn10 and Ferrari and Michelin and Shell, etc.
The fact that these manufacturers don't usually go after these thieves doesn't make it legal. But sometimes they do go after these people which is why most of them use aliases. You can also see groups of creators now altering their work to be similar to but different from established manufacturers. URD makes the Darshe instead of the Porsche. All of the URD cars now have fake logos that are similar to but different from the original copyright holders. This is because if they didn't do that, they could be open to a very substantial lawsuit.
Your comment about, "It's up to the individual to follow their moral compass." is true when it comes to the people who steal content from other games. It's also the responsibility of the downloaders to follow their own moral compass when it comes to paying for stolen content. Yes, people seem to always take advantage when they can, but that doesn't make it morally correct. I think the problem lies with those who create things vs those who only take things. If you've ever created something popular and tried to protect it to get compensation for your hard work, only to have it stolen, you know how terrible that is. Temper that against companies that overreach from their copyright and try to control anything that feels like their copyright (like Facebook did when they sent their lawyers after anyone with "Face" or "book" in their company name, making millions of dollars in lawsuit settlements).
Food for thought. Hope this sheds some light on this complicated issue.
