I feel at least a part of it is this idea that you can form a community around just liking a game, but in the absence of any actual 'community actions' (i.e. without any sort of community wide collaboration) it just collapses into circlejerking, making the same jokes hundreds of times and gatekeeping, oh and also lashing out at anyone who criticises the community or the game itself. It varies from game to game how much the community fails to feel like an actual community, I'd say the more collaboration there is the closer it becomes to really being like a community, for example, take dwarf fortress, the game is extremely confusing, it looks like the pacman overflow error all the time, a third of the gameplay mechanics are bugs that everyone liked so much that they were just never removed and it's incredibly complex; on the other hand, it is extremely easy to mod due to how low tech the graphics are (every creature is represented as an extended ASCII symbol), and people are constantly working out how to do new things with the mechanics so the community has come to have this warm feeling of collaboration rather than the elitist nature it could have taken on.