Everyone has their justifications and biases, and it's something drives both Allison and Derek's distrust towards one another. Isaac and Erica may never have killed anyone but Allison had heard them gleefully talking about how they were going to kill Lydia. Her best friend. So she's not justifying what she's done but they weren't exactly innocents either.

No one in Beacon Hills is.

"My dad spent some time working with Japanese businessmen when he was younger-- he might know something too."