What I notice in this community much more than any other gaming community I have been part of is that this community seems to heavily tries to downplay the toxicity ingame. For example: Someone calls you an idiot or other slur to get a reaction out of you?
One of the most common things I see on this forum is this response to that: "Get some thicker skin."
Second most common thing, which is effective, yet still heavily downplays the toxicity ingame: "Just mute them."
The second response isn't as bad as the first one, but both easily try to deflect the toxicity ingame. I've already seen this happen where a group of premades decided to pick on one player in the game to the point where the player afk'd and then the three had the audacity to ask in /all chat to report their teammate for afking. Even though it was on the enemy team, they were easily harassing the person who afk'd in /all chat.
The League community is extremely toxic, and I already know many people who have told me that they don't want to be part of this community simply because of that reason. The community both in the forums and ingame heavily downplay the toxicity of the community and that is what makes this community on par, if not worse than the Call of Duty community.
tl;dr: The league community is extremely toxic, and if Riot doesn't address it, it doesn't matter if the game is good or not; people will still have a negative opinion about the entire community if the community doesn't change its attitude about the minority who end up representing them at this point.