For me and most people I know, online games are no longer playable without premades(and the more the better).
League being toxic was a meme for long but it is becoming very true and it got so much worse over the last years. While the IFS can instantly take care of huge abuse certain behavious slip through. Especially emote/pingspam abusive sarcams and ingame trolling actions to %%%% up a single player will not get punished unless reviewed after a huge amount of reports.
It is not just league it is every single game. Toxic behaviour is becoming more and more of an issue everywhere and in the example of league there is barely any difference from level one to low diamond. Other games I have played in which the toxicity is very high as well are any moba I have ever tried, most mmorpgs and most speedrunning communities. I do get BM especially between rivals in certain games, but consistent abuse over persons you don't even know in the respective game is just a no go and ruins all the fun.
Also I think unless Riot changes the punishment system to something that either tackles the initation of toxic behaviour or can filter different things than obvious chat abuse it is not going to get better.