If you got a 25-game chat restriction it means that you had received a 10-game chat restriction before-hand, ignored it and were valid reported enough times to trigger the next step up from a 10-game CR, which is a 25-game CR. Also, just because another player is behavior worse than you are doesn't excuse your own poor behavior. From the Tribunal FAQ and Ulanopo's Knowledge Base respectively:
That player in my game was far worse than me. Why am I banned???
I'll keep this one simple: those other players in your game that you thought were worse are probably also banned. Nearly 100% of the time, those players were banned even before you were. If someone is being toxic, just report them and move on.
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.
If a player retaliates and says something bad back, then the two of you have made a negative experience for potentially the other 8 players in the game. Rarely do teams start working together better when players begin fighting back—great games only happen when players cooperate and don’t make the issues even worse by fighting back and forth.
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.