Answer:
The given quote means that the victim is not the only one affected by the attack. It also affects and influences the others who are witnesses to the attack, thereby making them victims of the same hate or siding with the assailant in support of his/ her actions against the victim.
Step-by-step explanation:
The given quote is from Sara Farizan's "Here To Stay" which follows a young immigrant boy's life in school and his struggle to navigate life as an outsider. The story deals with themes of racism, identity, acceptance, bullying, stereotypes, etc.
The quote "[B]ecause hate doesn't just touch the intended target, it spreads to every person who witnesses it" means when one is a target of hate or bullying, he is not the only one who suffers the attack. It also affects the others witnessing the hate attack, be it as a victim or even as an assailant. the witnesses can either become one with the victim in the hate or side with the assailant and support the act of attacking the victim(s). This then spreads to the others, thereby making a wave of influence over the incident and affecting whoever it touches/ reaches.