Dear Britney
You're clearly making an argument in the form of a question. Has riot gone too far? I honestly don't think so.
You argue that you're being flamed for off meta lane/champ choices, the other that you're being banned for "defending yourself."
The summoners code is very clear on champ select.
"Being a good team player begins at champion select. Be open minded when considering the needs of your team. If you're the last one to pick, try to fill a niche in your team that hasn't already been filled. If everyone's picked and something stands out as a deficiency in your team composition, try asking for another player to fill the gap, or change roles to embrace that responsibility yourself. Remember, that by taking on a role you don't normally play, you'll learn more about unfamiliar champions and increase your own skill level."
So by insisting on playing Janna top, as has been clearly explained, you're NOT following the summoner's code. Riot is expanding runes/items to try to make more champs viable in more roles but if you're playing a champ with weak ap scaling mid, then you're blatantly making a decision to not fill a deficiency in team composition. Janna is extremely squishy. You WILL die every time you are ganked when you push to tower. Your text log and forum posts make no effort to explain why you believe Janna is a good choice for top lane, and the text log you posted where you mock the other team for exhausting a janna is a strong indication you're aware the choice to play Janna top is poor.
You say they started flaming, but you made a decision that reduced their odds of winning the game, and it seems you refused to justify it. You claim you're "defending yourself" from flamers, but YOU started this fight when you decided to play Janna top. You aren't just "defending yourself."
LOL is a fast paced game with little time for typing. Important stuff shows up in that text box sometimes. By filling it with your words, I don't get to see stuff like
"watch out mf zed coming bot"
because the box is full of you talking trash to your teammates.
Be prepared to explain your choices, politely and succinctly, if they're uncommon. I favor a doran's ring on MF, and I have to expalin constantly that she's an AD caster who uses huge amounts of mana and regenerates it very slowly.
You seem upset about is that the LOL community has declared your behavior in game inappropriate. Players of the game, not riot, decide whether you get banned. The people who chose to ban you felt you were ruining other people's games, and they'd rather not play with people who behave like you do.
If you don't want a perma ban, change your behavior. It doesn't matter how well you argue on the forum that you were behaving fine, if you continue this you will lose your account.
TL;DR: you WERE banned for being annoying. The people who reported you felt you ruined their experience, and the people who voted to ban you agreed. Are you seriously confused about why, or are you just trying to make an argument that the ban system needs some work?