So this game on its own wouldn't have resulted in a permanent ban. Have you gotten chat restrictions before or a 14 day ban? Everybody gets 4 strikes and if you were on your last strike even a minor offense can result in a permanent ban.
My guess is that the automated system honed in on the word "retarded" (the system cannot tell what context the word is used) and that combined with your other raging and people reporting you was enough to trigger a punishment. Even if other people are flaming you that doesn't give you the right to retaliate.
It is extremely rare for Riot to reverse permanent bans. However, you could submit a support ticket and try to explain that you weren't calling someone retarded (just the champion in general) and that you don't understand how the rest of your chat is offensive. My guess is that you're request will get denied the first couple times but if you keep escalating the issue you have a very small chance at the ban being reversed (though its really unlikely.)
Moving forward, here's some advice to avoid punishments in the future:
- Never use any word that can be construed as discriminatory or hate speech, even if its not directed at another person. This includes all racial slurs (even %%%%%), retard, autistic, %%%got, down syndrome, etc. Those kind of words combined with people reporting you will pretty much always result in a punishment, regardless what context you used them.
- Don't respond to people taunting you. Just mute them.
- Your team doesn't need to gank for you, regardless how many times you get ganked. If you are getting ganked over and over you need to adjust your play style and play very defensively. Also, let you team know that the enemy team is camping top and tell them to push other objectives or come top to set up a counter gank. That shows that you are intelligently thinking about how your team can win and not just complaining about getting camped.
- Put yourself in your teammates' shoes when talking to them. If you were the jungler and your top laner was talking like you did would you come gank for him? Instead of saying "omg I've been ganked so many times stupid jungler where are my ganks?" say something like "Irelia is constantly over extending and diving me, come top and its an easy kill."
- If you're getting stomped in your lane then try to get back into the game by roaming. As a top laner ask your bot lane to place a ward in one of the bushes behind the enemy and then teleport to the ward when the enemy bot lane over extends. This allows your team to get bot tower (which is global gold for you) and allows you to get dragon.
- If the enemy top laner can dive you 1v1 and live then you just need to back off and sacrifice the tower. There's no point in you dying to defend a tower that's already going to fall. Most people will hard push the lane and all you have to do is freeze the lane just before your inner turret and you can force her to overextend or allow you to catch back up in CS/exp. The danger of doing this is it allows her to roam more and gank you allies so you need to make sure you ward up the river between top and mid lane (since that's the lane she'll most likely go) and make sure you ping MIA (or even tell your mid laner you expect her to gank mid and to play safe.)