That doesn’t require an implementation - but that mirrors our regular patent office, which does not require physical functioning prototypes to demonstrate.
That's not always the case. For example, patents around nuclear technology:
Have you filed or read any software patents? Many are so vague that they do not embody any significant "idea" or contribution, and are mostly just a hindrance to actual innovation. And some are just plain stupid, like the patent to average two integers without overflow.
Like the parent said, a compromise could be "source or GTFO". But even that seems of questionable value.
The shit show gets to the point where many companies file patents defensively. They'll file a patent just in case their competition does it first, even if they have nothing to show for it. And this naturally affects smaller companies disproportionately because they do not have the funds to pay lawyers (there is a hilarious interview on Youtube of a small startup CEO that explains how his company spends more on lawyers than engineers.)
So tl;dr, we'd probably be better off without software patents altogether.