Currently the logic of the space administrator is that if there is a page that have restricted viewing which the space administrator doesn't belong, the space admin is only able to view it by removing all restrictions from that page.

A better way to handle it would be giving the option to the space admin to add himself into the restricted list therefore we can avoid removing all the users and groups on the restricted list.

With that, it would prevent the hassle for the space admin to add those users back to the restricted list again and also prevent the page from being unrestricted and available for viewing for all users.