People only say that when they are tilted and jealous of your team. I'm pretty salty myself if I constantly have to play 1 vs 2 or 1 vs 3 meanwhile my team is doing nothing useful.
There are things in this game that tilts the player or makes them salty.
Example what pisses me off the most:
-minion block
-totally random turret aggro meaning if you get dived by the enemy the turret wont shoot them
-totally random turret aggro#2 you look at the enemy funny and it start shooting you instead of the minion wave that is front of you
-luck (remember running away with 10 HP every damn time is not skill)
-team blaming you for them being idiots
-no sightstone support
-
--constant camping(babysit)
The biggest tilting for me is the constant camping(babysit). My biggest strength in LOL was the ability to win 1 vs 1 fights. With the change in the meta where the skill to 1 vs 1 was removed and toxic playstayle was introduced by introducing jungle catchup exp, removal of wards, overbuffing ADC's, damage meta. Enemy having a better jungle results in you loosing lane even if you are higher skill leveled makes the game way more frustrating then they were before.
If I get camped for 10 minutes straight at least 6-7 ganks even if only half the time it is successful, it makes you loose lane and tilts you. You cant carry your team if you are behind meanwhile they feed 4 vs 3 anyway.
It really pisses me off when people cant play without having his buttbody wipe his ass every 2 minutes. You say its team game. You are right but where is my team when I keep getting destroyed with no way to get back in the game? Oh right they loose 4 vs 3 and we end up loosing the game.
I dont like to flame and I'm very much not proud of it, but yes I will flame anyone for needing a constant babysit. They prove that they dont deserve to play against you and they are being boosted by the camper. (next time when the boosted is alone will end up feeding and ruining more games)
The real reason the game is toxic is that the games are not balanced. The team who gets more boosted noobs looses by getting stomped.