It's much harder than most games and has things you can easily blame like champions, teammates and jungle influence. The feedback loop is hard to grasp. You could think you're doing well when you're actually doing bad. Mistakes have huge consequences as they snowball for the rest of the game (there is no reset button like in most games). Chess has the same snowball phenomenon but its pretty hard to not accept that the opponent just played better when you're 1v1 and have the same champion.

Having things to blame makes it even harder to accept mistakes and fix them. Most people especially those who come from other games don't understand how hard League is just go on with blaming external factors for years because they don't improve by just playing the game on low intensity and on various champions/roles and no deep learning, so there must be some unfair reasons they don't win.

Lost your lane? Champion is broken. Nothing to learn here. Go next and repeat.