Sadly, the human reviewer at Facebook is quite likely to not have even been alive in 1972 (or not old enough to even remember the photo) and so it is likely the

Sadly, the human reviewer at Facebook is quite likely to not have even been alive in 1972 (or not old enough to even remember the photo) and so it is likely they are just following the "official facebook policy" without thinking, and thereby hitting the "censor" button. Note - this does not excuse their actions, but may put some context around 'why' it is happening.