|It gets worse, though: defragging makes data recovery even harder because all of those 1s and 0s are moved around and reorganized.|
Total deletion of critical data is a hot-button issue with big corporations that don't trust the multi-pass programs that write random 1's and 0's that supposedly render the disks unreadable and the data unrecoverable.
Please rest assured though that companies do exist that will delete your data in the most secure of ways. They will manually crush your data storage media. And if you think that because HDD's are magnetic storage you can easily delete them by running a magnet over them, even the incredibly strong neodymium rare earth magnets, please think again.
Suffice it to say that "secure deletion" of data is an study unto itself. And that "delete" and "format" are at best empty and meaningless descriptions of what actually occurs; and what occurs by no means should lead you to believe that recovering your data, even after multi-pass erasure, is employed is anything more than a little more difficult, i.e. "even harder".