First, this is a very edge case and a very weird example to put into the documentation. I don't know why you'd ever want to do this copy-paste exercise. But anyway, I suspect that you've selected and copied the "wrong" thing. If you single-click directly on the disk you'll see this:
![enter image description here](https://community.wolfram.com//c/portal/getImageAttachment?filename=Screenshot2024-04-09at07.03.50.png&userId=587987)
That indicates that you've selected the disk graphic, not the whole output. If instead you double-click away from the disk but in the output cell, you'll see this:
![enter image description here](https://community.wolfram.com//c/portal/getImageAttachment?filename=Screenshot2024-04-09at07.05.36.png&userId=587987)
That indicates that you've selected the actual interpretation "value", and copy-pasting that will result in the expected behavior.