If he had bloodied a few noses of other schoolboys I might see his point, but shooting to kill and going after a spurned date is a horse of a different color.
I got beat up for two years in grade 8 and 9 because I refused an invite to smoke and drink with the cool kids. I got labelled and bullied. Grade 10 I was too big for them, and fought back and spent the next two years beating up bullies. Not once did I think I should shoot up the place.