Hardcore gamer = someone who plays only cinematic grizzed white dude games and/or military fetishizing FPS
Casual gamer = anyone that is not a 15-25 yo male, and/or plays anything outside of the previously mentioned games, especially if those games are colorful.
So basically the gaming community is full of gatekeeping, misogyny, toxic masculinity and general chuddery. They make sure they're the loudest voice heard when anything about games is talked about, and won't be happy until all games a homogenous stream of bland, hyper-realistic but with a grey filter slog of mindless action with no heart or soul. And don't you dare force them to read any dialogue or story.
Minmaxing and metagaming drains the fun out of games. That's why I don't ever play multiplayer game modes unless it's something like doing shit on a minecraft server with friends (i.e. a scenario in which "metagaming" doesn't really exist)
There's a time and place for it, busting a game wide open and seeing how absurd a power level you can reach is absolutely fun too