Toxicity is bad, right? Sure, nobody likes to be called a "super %%%%" just because they gave up first blood. But what is the "toxic player" really saying?
Well, a lot actually. With a minimilistic vocabulary this player is trying to, in the shortest way possible convey the entirety a sentence in two words. Having to type out "Hey man, I just watched you walk up into the fog of war and try to kill a full health enemy without placing any vision. You just gave them the first blood gold, lost pressure in your lane and forced the team into having to work from a deficit." Is completely inefficient and the fact that random matchmaking leaves you with 1-4 new teammates each time you queue up leaves this open to occur again and again across multiple games. Lets not forget about the myriad of other coaching points that can be brought up in a game. I'm using first blood as an example here. This means that for the toxic player they are simply frustrated with having to deal with the same in competencies over and over.
What could fix this? Playing with a dedicated 5 man team where the coaching efforts are extended past 1 game.
In closing, I'm trying to keep this short to keep the attention span;
Toxicity is not inherently bad. It's born by multiple attempts at coaching in order to compete the objective; Kill the nexus. The lack of tougher requirements to enter ranked breeds toxicity as you have a multitude of players who have no fuckin clue what they're doing, playing in a section of an eSports League where they have potential to become Professional. ;)
Don't hate on toxic players. Ignore them, but at the same time try to understand WHY they are being toxic. It's really because they're trying to win YOU the game.
Be considerate and help YOUR team win. Learn to BE carried and BE a good teammate. Those are the two single most important things you can do to curb toxicity, it will dissappear as the incompetencies do.