What I get out of this, after reading through all the replies in these posts, is that:
1) These FaceBook and other cookies are kept on your computer regardless of your preference settings, removal of all website data, and multiple resets
2) Safari > Preferences > Privacy > Details shows a list not just of cookies, but also cache and local storage
3) The cookies shown, when Preferences are set to reject cookies, are actually being stored in cache instead of being rejected; however, to the website it appears that the cookies are rejected
3) This ability for cookies to repopulate themselves regardless of the user's settings and actions is a Safari security issue that Apple doesn't address and hasn't addressed for over two years
4) There is no way to prevent FaceBook and other sites from repopulating themselves on your computer, i.e., there is no solution to this problem
5) The steps taken by users to best protect themselves are:
- Use Safari with Preference Setting > Always Block Cookies; use Firefox for those sites that require cookies to access (such as signing in to Apple Support or bank sites); set Firefox to remove all data upon closing
- Use Safari > Private Browsing for every Safari session (I'm personally annoyed that this can't be set and retained under Preferences, but instead must be invoked for every Safari session)
- Use StartPage.com or ixQuick.com for searches that will not collect or share your personal data
- Reset and also Remove All Website Data on Safari often
6) Again, there is no solution to this problem; all that you can do is to protect yourself as best as you can