I remember a quote by Ted Bundy but never managed to find it again. It was in his post-capture years when psychologists were poring over him.
I'll paraphrase badly. He said something along the lines that in his perception, shy, innocent, vulnerable, gentle types were asking for it.
Sadists are typically excited by dominating as brutally as possible. So it makes sense that sensitive people would be their favourite targets.
(It's great fun having them as parents, too. Especially when it sets a precedent that later extends into adult relationships.)