It seemed to me like they're hedging until they know which side is more profitable to support. We don't know yet if slop will be widely embraced by consumers. Valve will be happy to profit from AI if it takes over from real developers.
The idea that there is a future where game devs don't use AI, while the rest of the industry does, is absurd. We do know that AI will be widely embraced in gaming, because the alternative is, what? The honor system?