Thank you for your comment, Dariush.
"...I know that this is 2 frame grabbing stereo" – I'm afraid it is not. I took it from a newsreel film as a still picture. So in this respect the starting point was a 2D image.
"...because his arm remains flat" – The depth map of the arm ranges from luminosity 232 (next to viewer) to 162 (shoulder). What should be wrong with that?
"...you should push him back to the image" – A matter of taste.
Cheers - J.V.