bann system is broken

in a game I played recently i got the most disgusting words and threats thrown at me. the enemy adc said the following things:

"i hope your mother got run over and will be killed by a bus" " i will find you and murder you and your whole cancer family" " your cancer family" " your mother is a cancer whore" " i will find you and cut your throat till you bleed to death" ( this is just a summary it was going on all game)

well as you can see this wasn't very nice. my whole team reported this player. and now a few days later i still see this player play games. Riot how broken is your banning system and what do you need to say to actually get banned?? this player made irl threats and you dont even remove such a idiot from the game. where is the line you need to cross before anyone gets banned? if you allow language like this