Check this out, this is a video by a high elo player explaining the problem of toxicity in league of legends, and is attempting to fix it. Toxicity has been really cracked down on by Riot, as it should be, but I do think its still a problem that needs to be addressed. Having a negative attitude effects your outlook on the game in a negative way that makes the game completely unenjoyable.
I also personally don't think the game is in as bad of a spot as people say it is. its really easy to jump to blaming riot for not balancing their game properly, and its easy to create unrealistic expectations for a video game that is obviously never going to be perfect. so i do think that there is problems with the game as a whole, but thats always been the case, literally always. this is no different. its people's outlook on the game itself that is making the game nonfun more than anything else, and thats what i feel like people aren't realizing. think about it, is any other game fun when youre pissed off at it? league isnt any different, its a game and like all games, is there to have fun not to get pissed off at. its understandable that people can get frustrated here and there because its a very competitive game, but spreading this negativity subliminally does take a toll on the community as a whole, and if people still continue to make this choice its ultimately their prerogative, but they should still be aware of the consequences of doing so.