the content you consume almost entirely develops your opinion and playstyle in a game, especially multiplayer ones. if someone impressionable were to play tf2 and started watching mr paladin's videos, they would definitely be more inclined to play spy. or if someone saw a meme build that did (x), they'd try it because the content they consumed involving it was funny or intriguing.
if they didn't like mr paladin's videos, say, they hate his sense of humor, their opinion of the game would be affected. they'd be less likely to play spy, or simply got annoyed with what he was doing enough to not want to play the game.
one who watches fall guys content and enjoys it might want to play the game and imitate their favorite youtubers, their friends, memes about it, etc. there have been some terrible, terrible practices spread around, like voting all one player off just because, or purposefully throwing matches, being stupid in general, etc. these players are pretty commonly seen playing the game and it's understandable to dislike them
Fair enough, but then those players will just eventually learn how to play the game as everyone else has, yes?
Like, i'm sure no one knew what they were doing when this game was new, but then they all learned over time
you misunderstand. people don't dislike these users for being new.