I think this theory that it's related to Kennedy's assassination may be a little bit stretched ( I obviously DO believe he was assassinated by his own people to cover up something happening at the time) but I don't think it's related to this. The Majestic 12 is insane though.
To this day, people would absolutely freak out if the government fully admitted aliens exist and they've been working to cover it up for many years. My own mother said she wouldn't believe a God exists if aliens were real. People are incredibly afraid of the idea that there's something else out there, something that looks completely different, yet are probably 100x more intelligent. But, sometimes I'm like, "Just admit UFO's and cover-ups already dammit so we can move on with our lives!"