Okay, I suppose I'll give this a shot. These are solely my opinions, people may not agree, I might not touch on everything, blah blah blah. The Summoner's Code stuff is hard to pick out, so I tried to give ones that I feel might touch on the subject. Here we go!
"Rammus[00:10:28] : stuck at level 4 cuz graves be takinga ll the xp"
You're making excuses here, throwing a teammate under the bus. You might have been unfairly picked out due to strange circumstances, but it's better to take the high road. Instead of picking out Graves, you could've mentioned you're at a lower level, so you might need extra farm/laning time. (see Sum's Code I, III, IX)
"Rammus[00:12:26] : Kat reported for feed"
Situational. She might have been, but without a replay, it's hard to tell if it's intentional. Calling someone out for feeding, especially without sufficient evidence, has a negative impact on the team. (SC every-one-that-mentions-positive-communication)
On the flip side, you gave some good constructive criticism that game, and your request for reporting AFKs at the end looks justified.
"Katarina[00:08:59] : annie come gank
Katarina[00:09:18] : or don't
Katarina[00:09:19] : thats cool
Katarina[00:09:45] : lets think of a scneario where Annie comes out earlier
Katarina[00:09:48] : and all of us live"
"Katarina[00:18:34] : wtf Trynd died
Katarina[00:18:36] : except trynd
Katarina[00:18:36] : bad"
A whole chunk of nonconstructive conversation and throwing teammates under the bus. I get the impression you might've been joking around, but it's impossible to tell through text alone. As a result, it comes off as hostile. (see SC I, III, IV, IX)
"Pantheon[00:01:33] : only a **** would call someone a **** for text in a game"
I'm not offended by strong language, but there's a time and a way to use it, and it's never good when directed toward someone else in an ambiguous way. There's a few times when you seem to be joking, sort of, but as I mentioned before, it comes off as hostile (see SC IV)
"Pantheon [All][00:14:09] : Not shuting up is within sumoner code"
See SC IV: "Enjoy Yourself, but not at Anyone Elses Expense"
All in all, I'd say you were banned due to misinterpretation by other players. Though it's not a super serious offense, it justifies a warning. Even if you don't mean something negatively or seriously, you need to choke it down unless you're familiar with the team(mate). I know, it sucks, but if they have to ignore or mute you, the player experience is already negative.
I'm going to buy you a set of summoner spell icon coasters for Christmas as a show of good faith. You are most welcome!