SpeedMaster, who runs the blog in question, has shot video from the side showing a slightly closed racket face at contact. It should be noted that the pros don't always hit with a closed racket face at contact and, also, the racket face is only slightly closed. However, contra some early theorists, empirically you can lift the ball even with a slightly closed face if you have enough racket head speed and a slightly upward swing path.
I'm convinced that video is the best way to see what is happening, rather than arguing about subjective feelings of pulling across, hitting thru, accelerating late or early. Who cares about these terms when we can just mimic the movement patterns of successful pros?