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.
A plurality trying to imitate proplay without actually learning why they make the choices they do (The rest are one tricks who just play their main). Its why you can learn to last hit consistently and climb to plat on the income difference. Learning "Bruisers are strong all rounders, generally picked for their self sufficiency. Picking them frees the jungler to play more around botside objectives like drake" is something most players never learn