In Petunia's mind, "that awful boy" killed her sister. She didn't hate him because he was a wizard but because in her mind he took from her her only sister. Petunia loved Lily, no matter what she feigned.
I walk down the crowded sidewalk when I feel someone grab my arm. He is a man with a tan jacket, a tie, and a blue shirt. I'm the Doctor. I need your help so just keep walking and I will explain everything later.