"Omg Riot banned me just because I said 'gg ez noobs'. What a bunch of babies"(Again, for permabans)
No, Riot banned you because we don't want people like you to contaminate LoL into becoming a game engrossed with a high negative environment.
You said you don't deserve to be banned for trash-talking because we're just babies & trash-talking "defines the game as fun", but what you actually mean is that you just wanted to say it because you think it's fun, whilst ignoring the victim's feelings about it & think that they deserve to hear it.
And no, don't use that "they didn't use the mute button" as an excuse to prevent the permaban. They would only want to mute you because they think you're just plain annoying or not taking the chance to retaliate against you. You should know yourself when to stop trash-talking, instead of filling the air with just negative words in-game.
Take it as another tip before you try to use the title above as another excuse.