Most of the criticism I have seen online stems from how Canonical (the company behind Ubuntu) plays fast and loose with the FLOSS ethos. The earliest controversy I can recall was the inclusion of the ‘Amazon shopping lens’ in its Unity desktop environment. There may have been earlier issues, but this one made mainstream headlines in the early 2010s. More recently, the push for Snap (its application bundle format), which relies on proprietary server-side components, which invited criticism.
That said, I still find the OS ideal for most users. It has been (and still is) a gateway OS for many Windows and macOS refugees, thanks to its strong community. It was for me nearly two decades ago, and I prefer to remember Ubuntu for the good it has done for the community.
I haven’t used Windows for more than a decade, and I am genuinely surprised reading your post that the game works in this manner even if with proton/wine layer.
I can’t help but think that this is an exception, and would attribute this behaviour to how the game is made. I wonder what other software function this way.