Labels management is not accessible when Issues are disabled (moved)
https://gitlab.com/gitlab-org/gitlab-ee/issues/20298
Issue Moved ToWhen Issues are disabled in a project you can access labels page by /user.name/project.name/labels or by selecting Manage Labels options at New Merge Request page Labels dropdown. But there is no other way to access this page. Since Issues is disabled in project, left rail item is not displayed, so all sub items in it as well.
In my opinion, when Issues are disabled, it should not hide Label management, since labels are also available in Merge Request and discussions.
Edited by Gabe Weaver