Toxicity is ill-defined.
Or, at the very least, it's not defined enough to prevent people from saying critique (NOT flaming, but actual critique; Exact words "Your job as the midlaner is to roam with the enemy midlaner or take their tower. They have no reason to roam unless YOU let them.") wound count as toxicity. Even, in a really extreme example, "I'll be AFK" isn't toxic, but acting upon it definitely is.
I feel like Riot needs to release a mass statement saying "Critique isn't toxic. Calling you an asshat is toxic."