You kinda have a short fuse when it comes to the spirit of "putting your all" into the game. I think that may be the underlying reason why you were banned. The whole "g F g" thing and afk till 20 seems a bit unnecessary and counter productive.
You could have toned down your attitude a bit, especially with the 4th game. I main Fid, so I completely understand how bloody frustrating it is when your team cannot initiate so that you can go caw caw caw on them, but typing in caps doesn't really help the situation. Then again you are using snowball items, so I can understand the extra pressure and frustration with a timid team. IDK, if it wasn't for 2 and 4 I'd have considered pardon, but the 5th put it at 3 v 5 in terms of negative attitude or verbal harassment (I assume that is what you were reported on).
Just tone down the smack talk, or take a deep breath whenever you feel the need to knee-jerk lash out. The community needs more competent Middle Fiddles
EDIT: You no longer get free IP for tribundal. So you can take that excuse off for why you got bamped by the tribunal. And if you are going to go all-punish mode, well then you ain't any better than those you are accusing. As Furd said, you were only found by a majority and not, lets say, strong or overwhelming majority. IDK, if that is the lesson you want to take away from this then, in all likelyhood, you'll be back here.