Conscience usually catches up to these 'insiders' or the 'people in the know' but unfortunately it happens on their death-bed. Just do a search for 'JFK assassination insider death bed.' There are over 34k results. In our culture, I imagine they keep these secrets out of fear and retribution. But when death, as they understand it, is near... They feel the need to cleanse their conscience before they move on to their next existence.