The terms gamer and gaming community are used by people to lump anyone who plays video games into a small digestible nugget. There is no single gaming community and the sheer size of each of the countless gaming communities dwarf most other hobby or enthusiast communities.
Most people promoting gaming on Linux are so out of touch that they think having Tux Racer playable makes a Linux desktop computer a first or even second class gaming platform. Having The Witcher 3 or Tomb Raider on Linux is a novelty or a way to win brownie points.
I'm not a serious gamer by any means, my highest played game only logs 403 hours of playtime, I've see people with ten times that. With that in mind, none of the games in my top 10 list in terms of hours (~1800 hours) played are available on Linux.