And that is where things gets interesting. The ethics of the situation. Even beyond copyright issues. Was your AI trained on data that you have the rights for, or not?
We then have to think of the base model. How was that trained? I have not formed a well reasoned opinion yet as to the ethics of training on social media and forum style data.
For me, personally, I don't have an issue with my own posts and responses ending up as AI training data. We can also argue that those posts were made on public forums, therefor in public. But does that argument hold true for everyone. Underlying that question, we have to consider the profit motif off the companies. There is a major difference between training for academic purposes and for corporate purposes.
Valve is probably smart in steering clear of the entire mud bog at this time. Not enough is known of how it will play out in both the courts and in public opinion.