It's been three years. Why has there not been any explanation on why toxic behavior is tolerated?
I first began experiencing this behavior regularly in season 3. It's now season 5, and it's only gotten worse. Prior to season 3, intentionally losing games or going AFK for anything less than an emergency was almost unheard of at higher ratings.
See this recent game, attached. Our last pick started off the lobby with things like 'gg riot giving me last pick in my promos, we lose.' We had no idea it was going to intentionally try to lose the game, but just as the game was starting, it said 'im afking to play hearthstone, ff at 20.' It was toxic as soon as the game started, and around level 6, it just recalled and went AFK. It came back later and just walked around, not doing anything to assist the team, but still collecting EXP. It then intentionally fed twice and went AFK again. It returned a few minutes later, and once again just walked around the map, following champions, but not doing anything.
The player in question has at least seven games where it obviously AFK'd, but didn't get marked as a leave, in the past week. There are more games where I suspect it quit later in the game or just stopped playing, like it did in this game, because the EXP vs. game duration and items vs. gold don't match.
This behavior occurs in probably 1/4 to 1/5 games at Diamond V, and it's completely unacceptable. There should be zero tolerance for uncompetitive behavior like this. This is more toxic than verbal abuse, yet these players can get away with behaving like this for months at a time. I can't mute players to stop them from intentionally losing games, and I can't see a single reason to tolerate this behavior in ranked.
If going AFK seven times in a one week period isn't enough for this player to be removed from ranked, what is? What is the reasoning behind allowing this behavior to go unpunished even once? Why doesn't a single instance of this result in a ban from ranked, or other punishment?
p.s. for bonus points, see http://forums.na.leagueoflegends.com/board/showthread.php?t=3355088 from Season 3. +422 and a bunch of examples of this behavior at Diamond I.
EDIT: And I just got into a game with a last pick who was intentionally feeding, because he's at 0 LP Diamond V and has nothing to lose. This was my promo game.