First of all, what happens on a different server has nothing to do with what we do on Runic, and is not a mitigating factor in any way, especially since the events here were entirely one-sided.
Secondly, you were not banned for swearing alone, you were banned for impersonating another player by using their credentials without permission to get them banned. You attempted to get another player falsely punished by breaking as many rules as you could in their name. This is among the most punishable offenses on the list.
Additionally, this was not your first ban offense, you have been previously banned for griefing, and then given another chance on the promise that we would not see any more trouble from you. With this, you glaringly broke your promise, putting your word's worth at not much at all.
So lastly, I'm not convinced. Carrying out revenge on your friend about something personal in a way that ruins the fun of others as well is not explanation enough to land you back in. If you're truly determined to play here again you can appeal again at a later date with more of your punishment behind, with more time to think about the consequences of your actions.