I teach biology so I will give my text book answer which, in my estimation, applies across all genres.
"A collection of all the different populations that live in one area"
which means I should also define population:
" all the individuals of a species that live in one area"
If I superimpose those two definitions to MD, then yes, it's a community. Necrovians, Golemus Golemaricum, Marind Bell, Loreroot are populations. we have sub populations with various alliances. No Man's land is where the game operates as community.
And I've been told I think too literally but sometimes my literal thinking can lead to metaphorical thinking. At least, in my head it does.