So, from a lore perspective or whatever the fuck you want to call it, why is Dark Immune to Psychic?
Ghost being immune to Normal/Fighting makes sense since ghosts phase through shit so punching them will do fuck all (why smelling them makes it so you can punch them is something else though); likewise normal being unaffected by Ghost makes sense as it plays off the idea of, 'pffft, yeah big bad ghost is gonna hurt me eh? Too bad they don't exist', or for another angle, it could go off of the idea that normalfags aren't spiritual enough to experience the realm of ghosts and thus ghosts also cannot interact with them.
Ground being immune to Electric is simple since grounding is a thing.
Flying being immune to Ground is also obvious since, well they're in the air, so the ground doesn't do shit to them.
Steel being immune to poison works since poisons don't usually develop to deal with fucking metal so yeah.
Fairy is fucking gay so I'm gonna ignore it.
But Dark being immune to Psychic, why? What's the reason? And don't be a smug prick and go 'well it was done for game balancing reasons' because I'm asking for the reason of Immunities from a mechanical standpoint.