how is this balance?

where to start...This is my first time complaining on the forums and i think is my first and last post here since i rather spend my time playing the game. The video i uploaded it is a vivid example of what most games are not only from my side but many others are facing day to day. I fully understand the way of many think or consider trolling in a game but to "act" or "be" a child is no excuse to justify what the player on the video did. Overall he ruin the fun of what could have been a 4vs5 ether way, not only the person wanted to intentionally feed but behave like a kid and that's what i'm trying to rack my brain trying to figure out "why" someone would behave like a monkey? it's absurd and overall a party pooper. There has to be a way to prevent such thing...I would rather have fun facing a 4vs5 than having 1 person ruin all the fun. The person wanted to feed and he did so by helping the enemy with gold and he achieve that by buying wards and and resetting his gold champ. As as matter of fact, we all thought we didn't had hope but somehow we were managing to hold a 4vs5 as you can see, but at the end it back fire on us by 1 person. There has to be a solution to this...Every month i see new ways to spend money on skins and champions but not much to increase the problem regarding it's gamers in this matter. Easiest way to solve this is to have a in-game voting system to boot/kick someone out of the game with the LP lost or a warning of an account suspension - assuming everyone including the enemy team agrees to such trial, Rewarding good behavior is not going to help address this issue..it would be by showing solutions towards those "trolls" in ranked games and then reward those who are less of a threat. I'm not asking for sympathy but rather "help" figure out a way to solved problems like this within the "community" or "Riot-staff".

And for those who will ask what elo or type of game this is: Plat tier/ Ranked Game.