I don't have a perfect answer, but I think this topic deserves a louder and more direct conversation due to the impact it has on games. (Oh No! Am I getting down-voted because of petty narcissistic NEED to devalue something that conflicts with your emotions? ANY down-vote to what I'm saying here means "I got under your skin")
I'm sure this is a problem more-so with "lower elo" brackets, but I've noticed a lot more petty behaviors (especially coming from junglers) who are just out to start stupid fights (with teammates) for no reason and/or mess up the game in a variety of ways... to then engage in smugnorant narrative warfare and frame it all as "you should have leashed better. get taxed noob"... who flame you if you don't make everything easy and perfect for THEM... who only show up when they can "clean up" and get the kills so they can engage in the "my kda is better" narrative-ego-masturbation because they're so desperate for accolades and validation (and are willing to throw games if THEY aren't the best on the team... just so they can feel like they "won" by making it happen to punish the teammates who wouldn't LET them have their way).
Nightblue3's antics are actually very appropriate to call out and highlight here... that was a version of what I'm talking about
Right now, there's really only punishments for excessive bad language and inting/afk/leaving... but those are just symptoms of a larger issue that presents itself on a spectrum. It's easy to hand out a chat ban for toxic language or a suspension/ban for consistent behavior that throws games... but that's not going to do anything to soothe those reactive-wounds that they have in the face of what ever triggers them... no, they just got punished for already being an "abused" person (on some level) and not knowing how to process it in a healthy way that allows them to react better... but it wasn't explained to them what needs to ACTUALLY be addressed and changed. All they hear is "YOU WERE BAD!" while they were just "having fun" or (stupidly and immaturely) "standing up for them-self"... yea, _that's_ not gonna cause "spite" and "resentments" at all.
What happened to those info graphic videos that were coming out for a while? RIOT, you guys have control over the interface. If a person is acting excessively like a petty child who can't help but take their frustrations out on the people in their games, lock them out of being able to play and feed them some education on narcissism that they have to pass a quiz on... or SOMETHING to _that_ "creative end" where you MAKE them face how that kind of behavior is unacceptable.** RIOT... if you are so hell-bent on not imposing "prisoner's island" as a rational response to the kind of people/behavior I'm describing (and only breaking the ice with my description)... then you need to do something ELSE that actually deters this behavior**. They don't see how there are repercussions _(literally just had a convo about this after a game where he flamed for no reason and it was proved to him, and where the person said "never said i was a good person"... silently acknowledging he's doing this just to FEEL superior/better in the face of subverted emotions/expectations)_.
These people need to be taught how to "play nicely with others"... take a firm stance, RIOT... and use your influence for some "greater good" by teaching the gaming generation how not to make the world worse through petty short-term-gain emotional revenge mentalities.