I do not believe anyone has ever suggested that there should be a G0 down to the top of the workpiece. That would be relatively insane. However, there is nothing wrong with a G0 down to clearance height, safe height, or retract height, as long as those parameters are set properly.
My CNC mill is nothing special, but it does what it is told. If directed to G0 down to a preselected height "above" the workpiece it does exactly that. It never overshoots. I also measure the top of the workpiece to the full required accuracy for making the part. If someone does not care to set the workpiece touch-off carefully or does not care to make sure the safe height and/or retract height are correctly set they should not complain about the CAD-CAM software.
Gene