Sorry, but I was willing to report halfway through the first game. His words to Zyra may have been "competitive jests" (though I doubt it since he repeated them afterward in team chat), but the long list of abusive comments toward his own team was more than enough for his ban to be deserved in my opinion.
Also, you're ignoring the fact that, as a permaban, he went through the tribunal several other times AND THEN was reviewed by Riot. This isn't exactly a sudden thing.
As to his years played, games played, or ELO rating... so? What difference should it make who you are? If we were to let him go for that reason, it would destroy the credibility of the system you criticize for... a lack of credibility.
Don't misunderstand me, the tribunal CAN be wrong, especially not long ago when people were given IP to judge. However the chances of the tribunal being wrong five or six times, then Riot's staff I find to be abysmally small, especially after reviewing the reform card.
There is no different list of rules for the high rated players. There is no different list of rules for those who have bought riot points. It doesn't matter if you're the unquestionably best player in the game. You break the rules, and you will be punished.