It affects your enjoyment and immersion. If the game introduces you to elves who are not white, it takes you out of the immersion. Or if the setting is Europe in the middle-ages, you don't expect to see many asians, or gay people, or guys pretending to be girls.
Valve has already been doing great things for gaming on Linux, they don't need this. Bazzite is still doing its things and sharing it with anyone interested, they don't need this. This feels like a circlejerk group who might try to be relevant by pushing an agenda