Isn't the question at hand why Victor despises Sharon though? As such does the roles anyone else played or even her mental health supersede an understanding of why he would despise her? I don't think it does. He is entitled to his feelings about her and her roles in various moments of his life without giving her any compassion, consideration, or even placing an examining eye on his own checkered past.
Great point SS. Who cares about anyone else, plus neither Billy or Tucker abused his family members or burned down his home.
He is absolutely entitled to his feelings and doesn't owe her a damn thing. She has been nothing but a soul sucking leech on his family since she stole Nick from her bff.