[Alaska Wolf]

he chose the school to get revenge against the administrators he had argued with the day before.

Maybe you can tell me why a 20 year old would have an argument with administrators of an elementary school ?

[palmer]

Maybe because he had no interaction with any of society. No friends, no job, no education, no other outlets. So he might have been looking for some sort of interaction but lacking social skills he could only go there and argue.