On your map, all of the pyramids and most everything else, as well, have sides that are due north, south, east, and west. It must have been their thing back then. The Great Sphinx lies due west of the south wall of the Khafre pyramid. It’s not obvious that this all was done for the reason implied in the article.
The question that I have, though, is how they determined the directions accurately. Using only the sun, that would only be possible on sunset the days of the equinoxes.
If you put a straight stick in the ground, the shortest shadow is due north (when north of the Tropic of Cancer). Drawing the perpendicular is easy. You can also use the sunrise and sunset shadows and bisect that angle to get the north-south line any time of the year.
I have heard that they also used the north star at the time, Thuban, to mark north and that estimates on the age of structures could be made based on deviation fron true north caused by orbital precession.