I can only think of two possible ways:per article linked above: a fellow student told the 14 year old that he had stolen $30 from the 14 year old's girlfriend?
How does this fit into the "honor sub culture?"
A. There maybe a different side to the "Who took what from whom first and why" claim. In the end, one can be both a victim on one occasion and tell a spun story on another occasion. I dont have any idea if that occurred or not.
B. Alot of honor sub cultures tend to stack the deck when settling honor disputes. Very few of the romanticized western duels were one on one fights against a prepared opponent. The Hatfield and McCoy feud featured alot deaths where the victims were both out numbered and ambushed.
I have a feeling that a good number of samurai duels were sake fueled ambush slashings- not sublime encounters after a tea ceremony. Hawaiian surfer beat downs tend to occur when the honor enforcers have a distinct advantage. Middle Eastern honor killings? Plenty of female victims. Likely armed males engaged in shaming conduct get the benefits of the doubts.