I'm not a psychologist either and my opinion isn't as a professional,but rather an amatuer."Wouldn't a true sociopath be able to lie without getting angry about it?"Good question.Maybe/maybe not.They experience anger just like us.They're also consumate actors,so if "anger"is appropriate at the time......
Clinton is not only a professional liar but a professional actor. I think in his appearance with Wallace two things were at work: First, it was partly contrived. He was putting on a show for the Dem base and performed accordingly. Second, even though he was putting on a "show" I think there was real anger there.
The anger came from the threat to his legacy. All human motives are complex and I think one can be a sociopath and still be genuinely bellicose and defensive.
I think Drudge had the best reaction to the episode: He said Chris Wallace should have had some mace handy!