No, it means they're older accounts with e-mail logins, and the person selling the account doesn't actually own that email.
The account I own was given to me YEARS ago by an old friend, and it is an email login. I've since gained control of the email (old Hotmail, it expired and I was able to re-create it) and I'm assuming the same concept applies to many of the aforementioned accounts
The account itself can still be associated with a different email for password resets, steam guard, etc.