We have like 10 categories. On the admin side we see all 10 on the sidebar, but new users only see one - general. But if they click “all categories” they are taken to the /categories page and they see them all.
Permissions etc. are all set correctly. Is there a specific display setting we are missing?
keep in mind that users can override this with their own customized categories section in the same way you can (clicking the pencil icon beside the category header in the menu).
note that there is also a similar default navigation menu tags setting for tags.