I don't know why it was deleted. I would guess it might have had something to do with the user's apparent unwillingness to pursue the issue; he seems to have just given up.
I wouldn't have deleted it, but I would have closed it as a duplicate of Securely wipe a headless remote linux serverSecurely wipe a headless remote linux server which is pretty much an identical situation and has a few good ideas he doesn't seem to have considered.