How does the ban system even work? (Got banned)

Im sure many have heard this tale before and all but im still gonna talk cus goddamn do i wana say this. How is it that i was banned? My friend is a relatively toxic person and he is definitely worse than me .He is toxic almost every game and just starts wars with evryone that says something bad to him. I tend to not write much in game only when im directly asked a question besides that not much since i prefer to keep the rage outside of the game even if it means like hitting the table. So plz oh plz tell me how is it that i got a 14 day ban AFTER 1 GAME of being srsly angry and toxic to the enemy. (i was literaly gonna stop playing after that game because was too angry to keep playing but than saw the ban) All i want is an explanation on how i got banned after a SINGLE game of being an a-hole And the things i said were definitely awfull like kys (kill your self) and i realize that but when someone calls you a brain dead retard and worse stuff MULTIPLE TIMES that person doesnt get banned?