Gabe buying a yacht makes the company evil or something? What's your point?
Valve has single-handedly massively contributed to Linux gaming. Buying their products is obviously beneficial to Linux gaming as a whole. It's in their best interest to continue their trend of supporting and improving Linux gaming.
I think it's important to note that it's not just gaming, but the improvements have cascaded over to regular desktop users as well: I'm taking about improvements in the kernel (for AMD CPUs mainly), improvements in the graphics stack (Mesa, amdgpu drivers), improvements in KDE and of course, improvements to the Wine project in general (which goes beyond gaming). Anyone who's been closely following the FOSS scene can see how the progress in these projects have exploded exponentially over the past 3-4 years, thanks to Valve.
And with the most recent announcements, we can expect to see a similar sort of growth in the FEX emulator and general ARM support for various projects, which is all every exciting even as a non-gamer.
Valve has single-handedly massively contributed to Linux gaming. Buying their products is obviously beneficial to Linux gaming as a whole. It's in their best interest to continue their trend of supporting and improving Linux gaming.