Why you shouldn't care about "Riot's" label of toxicity.
It doesn't mean that you are a toxic person.
It simply means that the playing grounds for LoL and player behaviour is heavily monitored, scrutinized, and emphasized.
I was thinking back to my DotA/DotA2 days and what I had to go through in order to win a game (and reached 4800 MMR @ my peak). Firstly, there is AP or CM as the go-to ranked modes. I played CM for a better chance at team co-ordination. However, the difference is that roles aren't pre-assigned. You have to communicate with each other to discuss who goes where. Some people auto-lock ASAP as soon as hero selection is done and DGAF about the rest of the team yet still want to win.
So half the time, I would be a support. During the time I played, a standard roster would include 2 supports, 1 hard carry and 1 offlane. Lanes can go anywhere from 3-1-1 to 1-1-3 to 2-1-2 to 1-2-1-1, etc. Many many different ways of setting up the game. BUT, the support would always have to buy a courier, sacrifice farm, stack jungle creeps, TP/buy dust and look for ganks ALL the time while only getting gold through assists from kills. There are no "gold" items. There is usually no way to farm gold or passively gain gold yourself. Oh, and when you die, you lose gold. Even better, the role of support is usually divided between 2 people. Sometimes I would get stuck as the only support otherwise we would have none.
TL;DR- the main point is:
Just imagine how much a person has to tolerate in the support position. The selfishness of other players. The selflessness required to boost the team. That was me. I played 50% support, 30% offlane & 20% hard carry. Eventually I just stopped going for the hard carry role because there wasn't usually a support who was willing to have their ass plowed for the sake of their own team.
Yet by Riot's definition, I would be considered toxic. It does not matter how much you do, how much effort you put in, how much you care about the win. What matters is "how you respond" to other toxic players. Are you going to mute them? Are you going to babysit them? Or are you going to occasionally flame back?
I do all of the above.
Honestly though, the aspect of emphasizing reporting has eliminated the motivation to win as a team. When people look forward to reporting their teammates, the team falls apart. Why would you want to help someone who wants to see you fail and/or punished?
Riot. Let people flame each other out. As long as they aren't personally attacking someone i.e. (religion, race, kys, etc) then let them be. Stop prioritizing the aspect of banning/punishment as a "win" for players who are vindictive. Half the time, the person who is doing the reporting SHOULD BE reported themselves. They are seeking to cause disruption and capitalize on people who are emotionally invested in this game. As someone with over 13 ridiculous wasted years of MOBA experience, I can say with certainty that I know what I'm talking about. I've been the person who legitimately tries yet falls flat on their face. I've also been the person who low-key trolls just to blow off some steam. I know exactly how it works and how to "game" the system.