The "All courses" button is still shown to non-administrative users regardless of the state of "Site Admin -> Courses -> Hide All courses link".
I attached a screenshot from the perspective of a non-administrative user who just logged in.

This bug was meant to be resolved for Moodle 1.9.9 but is still present on Moodle 2.7.3

There is a workaround.
In the "Additional HTML" page, paste the following lines into the "Winthin HEAD" text field:
<style>
.paging.paging-morelink

</style>