I wouldn’t quite go so far as to say it’s gone “mainstream” since you still have to be moderately nerdy to know about it. I get your point though. This is one of the reasons I am so happy the Steam Deck exists. Before Valve released the Steam Deck nobody wanted to make games for Linux, so Valve said “fuck it, we’ll do it ourselves” and proved it was not only possible, but a better experience overall. While not all games work, having 78-80% of your game library work on Linux, with no Windows OS performance tax, is a great experience. Even with the Proton compatibility layer games generally run faster than on Windows.
I feel like you are taking this way more personally than it’s intended. Most companies write stuff like this so the government can’t sue them. Basically, Microsoft is just covering their own ass.