I did a lot of research and reading on the differences between the various personality disorders during the fallout from the Columbine Shootings, and the Casey Anthony investigation/trial. I really wanted to understand how they could do what they did. I find the psychological aspect of these criminals fascinating.
You didn't address the part of my comment about the family environment though. What abuse or hardship did any of them suffer? You believe sociopaths are a product of their environment. Does a comfortable lifestyle and being somewhat privileged (or in Joran's case REALLY privileged), combined with extreme enabling, provide that type of environment that breeds a sociopath? Maybe if they came from broken, impoverished, or abusive homes I might feel differently.
Joran van der Sloot, Eric Harris, Casey Anthony and now Jodi Arias are not people who were sexually abused, physically abused, emotionally abused, or victims of an unstable home life. So how can you classify them as sociopaths or BPDs? You said it yourself, nature vs nurture. In their case I would very much have to conclude it's nature.