What exactly is considered "negative attitude"?

So last game someone accused me of being a flamer. I admit I cried, complained about the champion Zed, I tilted alot, but I did not flame. The player reported me of "negative attitude". I am certain that I did nothing wrong. I did not attack anyone, nor did I insult anyone. If anything that player attacked me; threatened to report me. But I am confused now, because I have never seen a single player who got punished for being a crybaby. At least I never got banned, even though I %%%%% alot about "this champ op" and "how is this balanced". The enemy doesn't see what I am typing since I have /all chat disabled and I never attack allied players. So I ask, what exactly is considered negative attitude? And is %%%%%ing about the enemy champion (not in /all chat) okay?
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