The software is set up to provide the best search engine optimization (SEO) possible. Instead of deleting content, it is much better for SEO purposes to reuse or redirect the content page that you would like to delete.
A content page can be edited and repurposed by just deleting the text or code on the page and then adding the new information.
Or alternatively, the page can be redirected by adding a new URL to the 'Alternate URL' field. A user clicking on the old url will automatically be redirected to the new page.
Also - Your MemberGate site is setup as a database that has a set number of "spots" for your content. It's not good practice to delete parts of your site because once you have deleted something you cannot retrieve it. When a record is deleted, it creates a space in the database that cannot be filled with other information.
Instead of deleting something it is better to set the item as inactive and move it to the 'Work Pages Category' to use it in the future. In the meantime, the page content can be deleted and the title set to "Reserved for Future Use" so you can easily find pages that can be reused.