I think what creates the confusion in the hesjedal video is that he is on a steep slope, but the angle of the video obscures that. That explains both the spinning wheel (caused by the bike slipping down the slope a bit while the wheel was touching the ground, causing the wheel to spin) and his somewhat awkward motion when he stands up.
What makes you say he was on a steep slope? Nothing about the background suggests that this is so (for example, all of the cars in the car park below). Also, if he was on a hill, the bike would have to have somehow had enough angular momentum to spin back up hill, as it appears to do in the later part of the clip.
