Hate Speech vs Criticism
Harassment and hate speech should be bannable. But criticism, teasing and banter should not be. All it does is empower overly sensitive players to take out their hurt feelings on others.
Here are some examples:
BANTER: Trash talk with the enemy laner
I've had my own teammates flame, call me toxic and threaten to report me for bantering with the ENEMY laner
TEASING: making fun of someone for missing a skill shot
I've had people lose their shit and start inting for going "lol" after they miss something or die
CRITICISM: If I'm mid and the enemy mid laner is at my tower with no health, there's nothing wrong with going "Yo jungler, free kill mid come on man."
The best way for him to grow is to understand where opportunities are and what are mistakes