Over the course of the past years, I played many characters, got tons of them banned, kept some of them, but it helped me find out finally how RIOT's system for `Player Behavior` works.
So imagine you are a fresh face, a new player, you are not burdened by discussions of toxic players, you are exploring a brand new game. So you do the tutorial, play some normal games, level up 30, if by any magic you have not been frustrated by random acts of players (mostly because you dont understand the game yet), you decide to go to ranked. You start watching Riot events, competitions, you read in the internet guides, you watch videos, try to learn few champs and.... there it starts.
You have a weekend to play, so you start your journey in League of Legends Ranked. You are in the 'normal' stream of players. (this is important). So you play a game, then next, then next, you get randomly some trolls, afkers, inters, maybe flame here and there, it builds up (as many posts below this one indicate). So at some point you decide to chat back to the people (remember, you are new, you dont know how the chat detection system works). You get reported (actually you get reported every game, because everyone reports everyone if they lose). Then the chat system detects that you wrote negative word or two and you get a chat restriction 10 games.
This is where the fun begins!
You are now in the 'toxic' stream of players. You are no longer in the same stream as you were before. You are matched exclusively with people that flamed, inted or got any type of punishment. The RIOT logic is that they want to separate all the `troublemakers` from the normal player stream. BUT their brain is not enough to understand that this way they only create a bigger problem. (it is the same with racial minorities in any country - if you integrate them - you win, if you separate them - you get problems). So our new player, the fresh face that just got his nerves out for 1 game is now matched ONLY with `troublemakers`. You tell me - what are the odds of him not getting 10 times more angry over the course of his next games? What are the odds he will get his account banned?
But in the same time RIOT tell you that they are doing their best to improve player behavior.
P.S. On a side note. RIOT is a asian company. Their Behavioural Experts are asians that are accustomed to different ways, the asian ways. They have NO UNDERSTANDING of western culture, and they have NO PLACE in regulating how European or other countries write or behave. It is like putting a 5 generation brit to regulate bronx state. They can't even start to understand that sometimes words are just words, nothing more.