It could be both. I think some people might be attracted to children because they are easy to manipulate because of their lack of experience much as some adults seek out vulnerable adult partners. It might be to do with them not being able to relate to equals and needed an advantage ie powerful position.
From experience, I'd say you're spot on.
My dad sexually abused me between the ages of 11 & 13 and (with hindsight) spent his life manipulating people out of his and my mum's life, so it was only him she had to turn to and rely on.
He is an atypical sociopath and has managed to get everyone out of their lives that is capable of showing an opinion.