The problem is the wheel is rotating towards you, any slip up could be dangerous. With that setup it could be easy to rotate the edge and catch it. When the wheels rotate away from you, you hold the blade level a few degrees back from the top. Full visibility too.So you sharpen from the back side of the grinder? That makes sense.
I don’t think sharpening using the normal rotation in the location of the rest is any different than using a grinder for anything else. If the knife comes loose or the wheel comes apart, the knife will drive down towards the floor. I actually grind below the center point of the wheel so I can see the angle of the blade. At that point the wheel is moving away from me but not to the extent of how you are sharpening.