Why does Riot encourage players to AFK?

So the question is simple. Why does Riot encourage players to AFK in games. It's becoming a real problem for me. I don't even know if I want to participate in discussion because the same people that do it will probably just give me nonsense. It's been so frustrating I have had to uninstall the game. I want to play games for fun and not get stressed or aggravated because the encouraged behavior for players when they are mad is to afk. I really want to have fun playing this game, but it's been so long since i've had any really fun games that leaving seams like the best option. Why does Riot encourage players to lash out at other players by AFK? If you give a player what they want they will continue to behave that way. If a player wants to punish his own teammates by quitting so that they will lose. He will then quit and they will lose. Why is this mechanism supported by Riot.... eh i'm becoming repetitive