
Well the cause was his emotional scars, he had to steal milk every morning to survive (that sticks with you), kids beat him up and called his smelly rat (imagine if someone said you smelled, You'd feel self-conscious for the rest of you life & become obsessed with smelling nice at all times) and sex well that was an outlet for the trauma his shit of a father gave him every night before match, events of his life that left an impact on him emotionally, that was the cause of jinx

i get the milk and the cologne, but why /sex/? that's the one thing that didn't come from his backstory. milk and cologne had trauma related explanations, but the sex (which was consistently tied to abuse, power imbalance, and consent) just popped out of nowhere??? i expected the cause of that to be equally as heavy. for the cause of his jinx to be created by jk sleeping with someone off screen then magically winning a match is frustrating

that answers /how/ sex helped, not explain /why/ it had to be sex, which is what i'm frustrated about. there was no explicit connection between sex and his trauma like the milk and cologne had. the things you listed are what can you infer, not state. there was no reference to his dad the night he went to the club.
you'd think that with jk's jinx being the literal title of this story that the cause of it would be more nuanced and in depth instead of just. you know. "my jinx is reading books before matches haha maybe you should get one too!!" and jk going "yeah okay". the fact that it's brought up by a character we've never seen before and will never see again is so......... i mean come on. idk why i keep expecting more from this story?? i'm disappointed.