how is telling someone they have a mental deficiency ban worthy?

As a medical professional, I have yet to see any medical advisory/procedure body give standards of care for diagnosing someone with a mental disorder during a conversation taking place over a videogame in 20-40 minutes on average.

Because it's against the summoners code that you agreed to follow when you started playing this game dude.

dude...that's actual harassment as far as you went. Now not to say that the other dude couldn't have been doing the same thing... but holy crap where is your decency? Just tell the dude to piss off and move on. What good is it doing this? The risk is far greater than the reward... God I hope you don't talk to people like this in the real world to their face... [sg-ahri-3]

You could always post the logs...we might be able to give you some insight. Regardless; If you make another account, please do your best to just mute / report so you don't have to go through this again. Talking just leads to trouble.

Flame is flame. Riot doesn't care why you're having a temper tantrum, only that you did.

Honestly no one should have to tell you why this is not acceptable behavior. If you truly don't understand maybe you need to spend some time elsewhere.