Someone comes up on the street and hits you.
Question:
Do you (a) react as it's normally and expected and put the guy down and call the police or (b) simply let him destroy you, then call the police?
I'm sure it's a hard question with a very complicated answer.
"But this is not real life and you don't get hurt". Last time I checked psychological pain is almost as bad as physical pain. Abuse only happens because it's allowed.
Leaving that aside, context is very hard to detect by computers as of now, even in real life, context is something shaky and given the nature of the game, everyone has context.
Someone that said "go k**" to someone will say "yea but they were feeding" as an excuse. Of course this is absolutely retarded and they'd need a perma-ban for using that excuse on its own, but humans are built this way: they never believe they're wrong, no matter what, ever. Ever. This is why most errors happen in real life.
If they admit they were wrong, it's almost entirely due to an authority being ready to destroy them. Most convicts / killers, if no authority was around would just smile and tell you to f*** o**. It's not that they are truly sorry or so -
It's fear.
Fear that, unfortunately, as much as I love Riot, they don't convey. So, of course people will first think that they're not wrong and use any kind of excuses to get away.
The only real way out for Riot to fight off toxicity is to understand the context in which it happens:
No fear of an authority. If only we had a notification in game that'd pop and say "yo, if you keep going, we're banning you", the world would be a better place. But now business comes into play and you're thinking "Ah, maybe we shouldn't take a hit of our customers, even if they're toxic".
So then why do you have the perma-ban? These people are disrupting your money, as well as other customers. You're sending a message to a person that's being toxic to stop being toxic - pretty reasonable.
You can test this by simply just playing, at least on EUNE (where, I'm not kidding as I tracked games, you have at least 1-2 people wishing cancer upon others and 8-9 people being super toxic. EACH. GAME.). You'll almost certainly hear "hahahhaha Riot does nothing" in every game, because everyone's asking for reports on the losing team.
Back to the "in game notification that says you're gonna get nuked":
If only this was implemented, about almost all cases of toxicity would be wiped off. It's not as easy a task, but it's a step in the right direction, I'd know because my company has this "0 tolerance" towards toxicity. Whenever a customer would be bitchy / complain and try to hurt us with absolutely no justification, we'd instantly refund / ban that person from buying and instantly shutting them down.
So far, I'm doing pretty well for myself because of that.