Rito prefers to design games that reward negative actions more. It comes down to 2 buttons next to each player in the postgame. One button gives 'honor' which literally does nothing for the person giving it, and those receiving it if they are lucky to get it enough get a 20 pixel wide ribbon on the corner of their load screen portrait.
The other button however is the report button. This one is far more useful. You can use it as much as you like to try to directly screw over another player's account. Deserve has got nothing to do with it. But if Rito's automated system agrees with you, they get punished, and it even rewards this tattle tail behavior with messages indicating when the system has punished another player.
Given that this is a competitive PvP game, there's bound to be angry and vengeful players who can't wait to get to that postgame screen to get payback. This is compounded by all the problems and flaws in game design that we have in this game.
Got a player AFK from the start of the match? Too bad you lose LP.
Got a player being verbally abusive? Too bad you lose LP.
Botlane feeds 10 deaths in the first 7 minutes? Too bad you have to wait until at LEAST 20 minutes to forfeit.
The clock strikes 20:00 and the score is your team 3 enemy team 32. When you try to forfeit? "OMG it's ranked man I never FF" ( this is the same mentality that got Japan nuked... TWICE) -> too bad you lose LP, and you get to be held hostage by teammates for another 10-20 minutes while they drag out the loss.
Got an intentional feeder? Too bad you lose LP.
It's these kinds of things that lead to report/banfest that you see the fallout from in this message board.