The above explanations are correct. That said, if where you wish to look for Superchargers that are hidden by that ridiculous vertical strip that covers about a quarter of the touchscreen, you have to move the map to the right to reveal those.
I mean, what are they thinking? It seems with Tesla's periodic grand updates to its software, they take a relatively simple concept and turn it into an ordeal.
Sure, some people just don't know how to negotiate a map. Some people struggle to find their way without a gentle nudge in the correct direction. But I would guess that if we are driving along a long stretch of highway with few, if any, turns onto a different highway, that we are best able to judge for ourselves whether to stop at Supercharger X or to continue another 30 miles to Supercharger Y.
I think Tesla's assumption is that everyone--yes, everyone--will put their ultimate destination into the navigation window, and blindly follow the recommended Supercharging stops along the way. Therefore, there is no need to show all the surrounding locations with open stall data to let us choose.
Then, time of day is also a factor. Maybe it is lunch time, and the stop is at a spot with no or lousy food. Maybe it is in the evening and all the establishments with rest rooms are closed at location X, but location Y has fast food and a convenience store that are open.