Steps:

Go to roster uploader and upload this file
Go down to the bottom where it shows people who were in the guild but aren't any more (use Bradsfeet for your testing)
Select to delete that person
Upload it

Expected Result: Bradsfeet would be deleted from the 40 man dkp system

Actual result: No deletion occurs that I can tell

Looking into it after I figure out your decay problem

I didn't have any problems with this feature. Are you sure you had "Delete" selected? Sometimes I select "Do Nothing" when I mean to select "Delete."