Fix your match making
You wonder why people rage quit and are negative, and you think that punishing them more is going to fix that. Riot can fix a big portion of this by not making the games one sided before they even start. When you put me in a game against plats and diamonds, I'm more likely to rage quit than if I'm against other people actually my skill level.Its just not fun and I'm not going to endure through it. You might say that I'm ruining other people game play, well no, riot has ruined mine before the game has even started. So stop trying to blame the community, you can never stop people from behaving bad, but you can not give them a reason to. Fix your match making system.