It seems Dr. Borous carried his hatred of Richie into adulthood, seeing as the terminals stating his grades in X-8 say "Richie 'Ball-Lover' Marcus"  and every grade is an F-, except for science, which is F--. Also, during the basic level X-8 Data Retrieval Test, when the player character gets close to the coach's office Borous says, "Down at the end of the hall is BALL storage. For jocks who like BALLS, like RICHIE MARCUS. Do you hear me Betsy? RICHIE likes BALLS."
Dr. Borous apparently knew a girl he seemed to like named Betsy. She turned down young Borous's invitation to go to a dance so that she could smoke with Richie, leading to Borous's hatred of both Betsy and in particular Richie Marcus.