That is really anecdotal. I have bought many hard drives from liquidators as near new as being available in the original box and apparently sealed. I once bought a used hard drive from eBay which had mp3 files from billboard top 100 1960 through 2003 and also a bunch of porn on it. I of course deleted all the porn and backed up the music files before erasing it. I have no desire to have porn on any computer if I was to die suddenly and have my kids going through my data.
Used HDD and porn was a deal years ago. Kind of like a bonus.