I blame this "boys will be boys" bullsh
it mantra. That crap is HARMFUL. Not only that, but I also blame our media constantly heralding guys as the protagonist hero and the female in his eyes is some prize to be won.
This kid stabbed and murdered this girl but in his eyes, he probably feels justified. Yes, the kid is crazy, but his thought process in reaction to the rejection is disturbingly common.
Something is very wrong when a woman has to brace herself in defense when she's about to reject a guy's advances.