Valve is a business. When Microsoft introduced a Store they threatened Steam's market share. In theory Microsoft could one day update Windows so that it's hard to buy games through non Microsoft stores. Valve responded by investing in open source OS stuff. Their goal is to commoditize Windows, so that Microsoft doesn't wrest control of video game sales away from them. Commoditize your complement is a strategy as old as the software industry itself.
We've known all this for years, it's been discussed publicly and no one is hiding it. It always annoys me when people think we're in Lord of the Rings and one company is Sauron or another is Gandalf. It's all just business. To everyone who makes decisions, it all boils down to numbers on a spreadsheet. They want their number to go up.
What you SHOULD care about is competition. Valve would never have invested in all these OSS technologies if Microsoft hadn't tried to compete with them. They wouldn't be consumer friendly and they wouldn't make investments if they thought they could sit on their ass. They would just coast and enshittify (like Microsoft has in the OS space with its Windows monopoly).
We don't need good guy companies, we need strong pro-competition laws and strong enforcers of those laws. You can vote accordingly at the ballot box, and you can also vote accordingly with your wallet, buy stuff from the little guys.