The chat filter is there for people who would prefer not to see mature language in the game. It is not there so you can verbally abuse and harass others whenever you feel like it. We all agree trolls are annoying and frustrating to deal with, but flaming them only serves to fuel their desire for trolling even more, not to mention takes time away from the game itself as well as creates a negative environment for the other players in the game and ultimately accomplishes nothing important in the end. Though I know it's hard to do at times, don't stoop to their level and they'll fall alone if that makes sense.
For a more in-depth discussion of sorts, here's a passage from Ulanopo’s Knowledge Base:
People who report are simply being oversensitive. The mute button exists for a reason.
Let’s start with the Riot quote on this (link (http://forums.na.leagueoflegends.com/board/showthread.php?p=30696571#post30696571)):
Why is verbal abuse punishable if there is a mute button/language filter?
Players shouldn’t need to rely on features like the mute button or language filter to engage with other players in positive ways. When a player verbally abuses another player and forces him to use the mute button, they have already created a negative experience for that player.
Simply put, Riot says no. You can scream and cry all you want, but it is their house and their rules.
With that out of the way, I think the topic deserves some further discussion. The theory is that, if people resolved to care less, then they would be happier. I often refer to this as ”Argument from Stoicism” and I think it is a fairly weak philosophy because it places the burden on the person being expected to endure the behavior rather than the person exhibiting the behavior. “You should be able to handle it” is just a flimsy excuse for being a bully or a jerk. I have to be the bigger man so that you can do whatever you want? That hardly seems fair.
There is also the issue of how I spend my limited free time. Like most people, I am constantly required to make value judgments between the different forms of entertainment that are available to me and, let's be honest, we live in an age of nearly limitless entertainment options. If I'm having a bad day in League, I can just fire up Steam and play a whole bunch of games that don't require me to put up with someone's BS.
This is not an issue of weakness or thin-skin; it's a question of choosing activities that don't leave me feeling frustrated and angry. Too many of those experiences and I'll just find something else to do. Riot knows this.
Also from Ulanopo's Knowledge Base:
I should be allowed to speak however I like to people who started it or are griefing me.
I was provoked or taunted. I should be allowed to defend myself.
Why did you vote to punish me when others were behaving worse?
You should know that Riot specifically instructs jurors to ignore most of the conduct of people in a case other than the accused. The reason for this is rather simple: rather than one person causing trouble, you now have two or more. In my more cynical moments, I have phrased it thus:
Timmy, Tommy and Sarah are trapped in an elevator.
Timmy loses his temper and soils himself.
Tommy gets angry at the smell and decides to retaliate by soiling himself.
Now Sarah is trapped with two smelly idiots.
Dont be Timmy or Tommy. Stop ****ing your pants.
An informal poll of the Tribunal regulars shows that most jurors are willing to excuse a certain amount of response to someone who is attacking you, but that it isnt considered an excuse for you to become toxic in response. You get MAYBE one or two lines of response. Anything more than that and youre part of the problem.
From Lyte (link (http://forums.na.leagueoflegends.com/board/showthread.php?p=27540071#post27540071)):
We strongly believe that it is not OK to retaliate. If a player refuses to cooperate and says something negative, then players should ignore the player and report them after the game. Players can ignore or mute players by pressing the Mute button on the Scoreboard [when you hit TAB] in the game.
Emphasis mine.