Was a ban really necesary in this case?

I got a 14 days ban for calling a teammate names, and that's all. I know it was a bad thing to say and all, but was a 14 days ban really necesary in this case? Even though I did say that the enemy Aatrox was bad, I was not insulting him directly. I was not trying to pick a fight, in fact just loosen my teammates up because they were really hot headed, and started flaming me as well for not teamfighting, yet I didn't report them. Do I really deserve this ban? if yes, please tell me what else have I done wrong, I'm willing to learn from my mistakes. Also, I forgot to take a screenshot of the log, but I have them sent as a message to a friend. Here are the screenshots: https://imgur.com/a/PoVX0BZ https://imgur.com/a/5VWL27s
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