His team didn't take him seriously. They probably said something to rile him up some more. If someone is not in a good state of mind, I prefer leaving them alone especially after they tell you to stop. I think that they both deserve punishment. Him, as well as the guy(s) raking his chain. Because in both cases, they are being immature. One for going to such an extreme with the feeding and the other, angering him further when he warned them not to. If he thought about it with a calm state of mind, he really didn't have to go 0/15 in order to lose the game. He could have made poor decisions or not helped his team during key moments. As a Gold 2 in a Gold 4 game, its not difficult to figure out where he is needed to be during important fights. But he still went 0/15 trying to make a point. Which states that he wasn't calm but angry. This was his way of venting his frustration towards those teammates.
To answer your question, OP. Personality, maturity don't matter as much when it comes to winning in a Solo Q game as does your understanding of the game. Mechanics and intelligent decisions macros wise. Once you get the concept, its not difficult to keep abusing people with that concept which they don't understand. And even if they do, it also comes down to mechanical prowess. Personality and maturity may make a difference in a solid 5 man squad when pro's play. Or in Solo Q if you're leading your team who listen to you. Because in high elo's a lot of them play together with the same people. And certain players are adept at leading based on their previous performances with their teammates. Basically, teammates who rally around one guy because they believe in his ability.