I don't understand why you can't customize folder views for the Program Files (x86) and Windows folders on your system drive. If you right click on either of these, there is no "customize" tab. That setting, however, is available to their sub-folders, although it's mostly a farce. If you select all files and apply the General view to them, some folders are still stuck in Pictures view when you open them.

This is just one of the many senseless bugs in File Explorer that pisses me off.