This game encourages toxic behavior.
You know what's funny? How Riot goes out of their way to give chat restrictions and ban players for having a toxic attitude, when it's their fault this community is toxic. The core mechanics of this game are punishing and promote toxic behavior.
Before a game starts you get matched with trolls and such. There's always that one kid who says, "Top or feed" and is completely serious about it. If they don't get their way, they intentionally feed or just don't cooperate at all with the team which screws you over. Even better when that one kid instalocks when somebody else called the lane first, and then proceeds to completely get wrecked in their lane. If you dodge the game you get a short LeaverBuster penalty but if you start the game you already know you're starting it with toxic players who might make you lose.
You can be 18-2-7 carrying your team so hard, and still get completely wrecked because your bot lane fed. Imagine in Call of Duty if every time you killed someone you became stronger and your guns became more powerful, that's exactly the case with League. All it takes is 1-2 people to feed the enemy team to the point where losing is imminent. I don't mind losing but when you are winning your lane and see the rest of your team getting completely wrecked only 10 minutes in it's frustrating. This is a competitive game, people want to win and naturally get angry when their team doesn't cooperate right.
Now you're 20 minutes into a game and the enemy team already has 5 turrets while you have none. Their ADC and mid laner are fed so hard that if you try to engage them you'll get deleted. So naturally you try to surrender, but your surrender vote fails 1-4. Your whole team is getting smashed on to the point where coming back is already impossible but they insist on wasting another 20-30 minutes on a game that was a loss from the start. And now the enemy team is laughing at you in /all chat. How do you expect people to not get frustrated Riot? This happens all the time and is completely aggravating how you can't do anything about it.
Instead of fixing the core mechanics that cause the toxicity in the first place, Riot decides to just censor the community. News flash, when a player is chat restricted that makes it even harder for them to communicate with their team, only promoting toxic behavior. Chat restrictions and bans do not solve the problem of toxicity at all, in fact only making it worse. Times like these where it makes you wonder how League of Legends is the most popular game in the world with all of these apparent problems.