> If a customer bought a game that says it runs on linux, they should be able to play it on linux well

None of those games say they run on Linux.

  - Starcraft 2 is available for windows/mac: https://starcraft2.blizzard.com/en-us/
  - Anno 1800 is available for windows: https://store.steampowered.com/app/916440/Anno_1800/
  - Hogwarts Legacy is available for windows: https://www.hogwartslegacy.com/en-us/pc-specs

Every game I've purchased that actually says it runs on Linux, has worked beautifully on Linux (stellaris and factorio come to mind). Most windows games work beautifully on Linux too, but Blizzard isn't lifting any fingers to make it that way.