Problem with the claim is that placing ones hands in the position indicated can not be considered abnormal. Humans naturally need to do something with their hands when they are not using them, whether standing or sitting. For most people, it feels uncomfortable to just let them hang loose. I personally use finger tip contact with both hands on occasion as a stretch routine, although I admit I do not resort to this method very often. As a naturally born leader, Trump never sits back in his chair. As such, he does this to project himself more effectively into the conversation, but it means he has to do something with his hands when there is no desk or table in front of him. I believe it is nothing more than that. When he is standing and speaking his hands are always in motion with hand gestures for emphasis. When standing but not speaking he holds his hands at his side as he has done repeatedly when calling on someone to speak briefly at one of his events.