Why people use K/D/A as an argument?
It always happen on my server, but I am very sure that this happens at NA, too.
It is always the same thing: you are 0/9? You are automatically a troll, and everything you say is wrong, no matter how much you try to argue. You are 21/11? Then you carried the game alone, no matter how much your allies tried everything to protect you.
Granted that K/D/A can be an high evidence that someone is trolling, but K/D/A alone cannot be used to accuse someone from trolling and ruining the match. Otherwise, every support and full tank player in the game would be a troll, as they almost always end up with few kills but lots of deaths, due to their own playstyle.
Maybe someone died a lot because they are having a bad day, or because they sacrificed themselves to do lots of damage to the enemies so that their allies could finish them off, or they are just making lots of mistakes but have no intent at all to troll.
Once I was using 
, and ended up dying a lot because the enemy 
was constantly invading my jungle. Since I was building tanky (I had to purchase a 
to prevent more invades too, even before I purchased a complete Cinderhulk) I didn't had enough damage to finish off enemies. The combination of both factors meant that I ended up 0/4/3. My bot lane started to use this to blame me for the defeat and they insulted me a lot. Despite our efforts, the toxicity on this game prevented us from winning the game.
The reverse is also the truth: Often if someone had lots of kills but died very few times, they will use that to say that they carried the game alone, or that the allies had little to no contribution. For example, an ADC that ends up "carrying" the game, despite the fact that the support and the jungler had to peel for them, and the ADC still ends up taking all the credit for winning the game.
In short: K/D/A is by no means an argument that can be used to dismiss or endorse something. It may be an indicative that someone is trolling, but this is still not a reason to insult, or blame, or be toxic with anyone.
