Such traits indeed seem to have a genetic component. However, did Tsarnaev undergo a psychiatric evaluation? I would think he would have to, in order for the court to have the data necessary to reach a verdict. So I would have thought this would have been mentioned in the news if he were.
On the other hand, if he did have these traits, wouldn't that count as extenuating circumstances, leading to a lesser punishment?
Also, are you saying all terrorists have these traits? What about soldiers who kill civilians as part of collateral damage? I just find that hard to believe.