Glaring Incongruity (spoiler)

The four horsemen represent some sort of uprising by kids who have been neglected or abused by their families. The four horsemen are Kristin, Garrison, Corey and Alex. Kristin, Corey and Alex meet the criterion. But how does Garrison fit in? He is apparently an adult with his childhood long behind him and there is no indication that he was neglected or abused.