If you saw a game marketed as runnable on "all major operating systems", would you think it's deceptive, or at very least a poor choice of wording, if the game really only ran on Windows 7, 8, 10 and 11?
In the open source world, on a site called "Hacker News", "all major operating systems" would usually be thought to mean more than just Mac, Windows and Linux, particularly when it's chosen as a headline.
Also, claims by the author about ARM support are nice, but I don't see any ARM anything, anywhere, so not only is it not "all major operating systems", but it's "just the three most popular OSes, and only then on 64 bit x86".