A sociopath can be a whole different person with others than what he is really like when he is alone. That's why i think the videos of him don't show his true selfish manipulative nature.
Remember Scott Petersons mother-in-law, father-in-law, sis-in-law, they all stood by him in the beginning because he "is not the kind of person who would ever do something like this". All along he was maticulously planning how/what/where to kill Laci. And remember that voicemail that Rita Cosby left on his answering maching. Somehow his voice was recorded when he said of it in a mocking tone: "Hi I'm Rita, I'm such a nice lady". Nobody heard him but the answering machine recorded him somehow. Then he clicked delete as soon as he heard Larry King on his answering machine. Sociopaths can be totally different than they appear to their closest family.
Then we saw SP's parents and found out more about his early life it became obvious how he became so self-centered. Everyone covers up for the baby. Just like Bonnie and whatever the brothers name is are doing for HKS. And everyone else around HKS was doing it for him too for awhile, but they won't stick with him. Only his mommy and daddy will.