"Just mute" is for the birds
The whole idea that it's up to the typical player to "just mute" to avoid conflict, is nonsense. The problem lies in the fact that trolls are desperate for attention--if you mute them, they escalate their in-game behavior to flashing on top of you, running into your lane and inting repeatedly, etc. (don't tell me this is a fringe case either, see below)
Recently since my account has been banned, I've been playing on a smurf, muting all from the beginning so that I won't be "toxic". Ironically, what I've found is, I get griefed significantly MORE often for muting other players and not talking to them.
Finally, I think the logic that someone should get banned for addressing a griefer or troll is fundamentally wrong. If I'm driving my car, and someone runs a red light at double the speed limit, that driver loses their license, gets a ticket, etc. My driving privileges are not affected if I flip him the bird, or say something inflammatory because of what they did.