Getting to the bottom of the UAP/UFO whistleblower story
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My guess is the concept is deeply psychologically disturbing to a significant percentage of the population when faced with it as a reality instead of scifi.
Most find it interesting, exciting, or vaguely potentially alarming - in the same way an unknown rustle in the jungle might be alarming until you know it isn't dangerous. But not "deeply psychologically disturbing".
The only people I think could be genuinely deeply disturbed by the prospect of alien life may be deeply religious folks, surely not a representatively high percentage of HN visits.
My guess is a text-only message board with zero identity verification contains a higher percent brigading and sockpuppet content in general.