When deleting categories through the admin panel you must first delete all sub-categories of a parent category before deleting that parent category. DataPort does give you the ability to skip right to the deletion of the parent category (which will also delete all of its sub-cats). Although you would only be able to delete one parent category from the site through DataPort at a time, it does prevent you from having to delete each of its sub-categories first.
To do this using DataPort:
1. Click 'Products' at the top of DataPort. 2. Click the 'Category Information' button. This will display 4 white upload/download buttons in the middle area. 3. Click the far-right button (Download Categories from Store). Enter your secure URL and password. Once the download is complete click 'OK'. 4. Click 'Hide Category Information', you'll then see your category list on the left. 5. Click and highlight the category you wish to delete. 6. Click 'Category Information' once again. 7. Click the 'Delete From Store' button. You'll then need to enter your secure URL and password once again. 8. Repeat steps 4-8 for each category you wish to delete.