League (and mobas in general) are more toxic than other games, which is already a pretty high bar.
The primary reason is the large number and wide variety of skills needed combined with the snowball nature of the game. But let's talk about those skills.
- cs
- Warding for lane
- Dodging skillshots
- Landing skillshots
- Jungle tracking
- Wave management
- Matchup knowledge
- Objective setup
- Team fighting (could be broken down into multiple styles)
- Lane assignments
- Knowing when to farm or sacrifice farm
- Warding for objectives
- Communication
- Managing tilt
- Influence on team morale
- Item builds
- Suvival
- Knowing when to die
- Adaptability to game state
- Adaptability to teammates
I'm sure you could easily triple the size of this list. Naturally you're going to pay more attention to some skills over others, as will everyone else. And of course you'll be better at the ones you pay more attention to.
Imagine rating yourself on each of those skills 1-10.
Now you're thrown onto a team that likely has the same overall skill level as you, if you add those all up. What are the odds that the skills are in the same places? Across four other people? You're almost certainly paying less attention to some of the skills where your teammates are better than you.
The end result is that nearly everyone you play with looks worse than you. Likely much worse.
There's some variance between games, sure. This could just be a bad game for them. But... probably more often it's their average game. More often you're just not able to see how they win games.
So keep this in mind next time you think everyone in your game is terrible. They're probably able to make up for it somehow if you let them, even if you don't see it.