The hips slide forward in the downswing and if they don't the spine will not be in the right place at impact. If you actually teach someone to swing with the hips in a barrel so that there is no lateral movement then they will not be swinging like Moe. The pictures prove beyond any shadow of a doubt that Moe's hips moved forward (laterally) during the downswing.
I must also tell you that I fail to see the relevance of the fact that some part of the 'S shaped' spine might be in the same position at impact as it was at address.
