The argument is not based on raytracing, it is based on the fact that in the frame comoving with the sphere center there is no wobble. In this particular frame we know that the center of mass coincides with the center of rotation and the sphere (or wheel) doesn't wobble.I am not going to specifically address the issue of wobble until someone can give an exact equation for the height of the centre of mass of a rolling wheel (without slipping) with a linear velocity of say 0.8c and two opposite point masses of 1M each at any point point during the rotation. I am not going to base the argument on a ray tracing program designed to entertain the masses, rather than come to any analytical conclusions.
So, in the observer frame, the sphere (or wheel) cannot wobble either. You can't have physically different results in the two frames.
The raytracing program simply gives a visual confirmation for the above.