I recently was able to make the case to have my main account UN-perma banned! Some take aways from my experience;
1. Riot Support was nothing but helpful and respectful (once I contacted a real person). Even in the face of pointing out my toxicity, they never chided or put me down even indirectly. They were even willing to admit that the conditions of my ban were "Very immediate" and warranted another look. They pulled no punches showing me all the conditions of my initial ban though, careful to ask me, "Is this how you'd want to be treated? Really think about that." Something you don't really consider in the heat of the moment.
2. At first, I was combing my chat logs for ANYTHING I could use to make myself look better and like the victim. REALLY reading those chat logs in full paints a pretty clear picture of just how rotten I probably made people feel over a VIDEO GAME... While I was lashing back for being talked down to, I still chose to react back, and just as bad, if not worse so. This has pretty well solidified why it's not ok to do it back. You BE the bigger person.
3. The system is not perfect, and Riot knows it, and is willing to hear you out, especially if you're willing to really see their side of it. The support department has to deal with this vitriol we've spewed forth daily. Imagine that. Even in the real world, there are consequences for doing bad things to others, and sometimes a verdict is rushed or heavy handed, or something else can be done to rectify the wrongs committed.