My friend got permabanned for 1 line of text at the end of a game

I find it both hilarious and confusing as to why my friend got banned. He's been honour level 5 for a long time, but dropped back to zero due to afking in matches(his internet wasnt that great at the time and it was only blind pick, but he still came back and the afks were 5-10 mins long) Due to this, he got a 2 week ban and 2 months after coming back he got this, but the funny thing is this was a solo player report from a toxic vayne and the one line of speech he said was at the very end of the game(literally 1 second before defeat screen) deserving of ban yes or no?{{champion:32}}
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