Not sure I get the idea of oversharpening?!
Almost any person here knows that a razor can be too dull. But there is something like an optimal sharpness too. Just have a look at different razor blades from different manufacturers. You find different grades of sharpness and that has a good reason. If you have a very agressive DE razor and a very sharp blade, you might not be satisfied with the result. And because you don't have any kind of guards at a straight razor, you might not be satisfied if the blade is too sharp because it will peel off too much of your epidermis and the result will be some kind of razor burn or bleeding spots.
Ok, let me explain this a little bit furter. Do you know why a sharp straight razor is able to cut a hair in a few millimeters distance? Just reverse the hair to its opposite and hold it at the tip and try once more. You might be astonished but the hair test will not work anymore. How does it come like this?
It is because a human hair has some kind of scales, like the skin of a fish. And those scales have the direction from the tip to the root of the hair. And only if a blade is sharp enough, it can grip between those scales and gets enough hold to cut through the hair. That is a minimal sharpness to shave hair. But then you will feel some pulling and tugging because the blade is sharp enough to get this grip but it isn't sharp enough for a proper cut without too much force.
If you sharpen the blade some more, you will reach a point where the blade gets the grip and cuts the hair with minimal force and you will feel a smooth shaving experience.
If you sharpen the blade more, the lubrication of your shaving foam cannot protect your skin enough and the blade begins to grind off the upper layer of your skin, named epidermis. Because the epidermis consist of dead cells, it is not a problem but if the blade gets too sharp, it peels too much off your epidermis and your skin gets a major problem.
Therefore exists some optimal sharpness. A razor blade can be too sharp and can be too dull.
I hope, my explanation is understandable.