If this is a tactical move purely for selfish reasons, its not a good one considering the power Musk now wields. I think this is genuine from Gates. Saying it out loud maybe is a degree of performance, but I think he likely legitimately finds Musk's fascist support a morally bad thing.
Assuming all billionaires are constantly playing some kind of 4D chess game is just as bad being overly charitable when a billionaire says or does something that could be seen as good. Remember, Elon Musk has put himself in the spotlight constantly despite it often times hurting him financially, his desire to be liked/beloved as a genius is also genuine its just fueling frequently terrible decisions.
That said, Gates is still an egotist and obviously pretty conventionally selfish (at what I'd describe as a pretty human level, if an average joe/jane came to have billions of dollars they'd probably treat the money in similar ways as Gates). Gates doesn't deserve his wealth and Gates is no genius either, I just don't think hes a fascist or a sociopath like Musk is.
You point out that the game wouldn't exist without exclusivity but then immediately point out that it totally could exist if the profit motive did not run our economy.
The existence of exclusives is a form of cultural capture by capitalists (As is copyright). I would argue that it would indeed be better if Alan Wake 2 was never made if it meant that exclusives stopped being made entirely, and Alan Wake 2 looks like a game I absolutely want to play.