I'm fairly confident about it because I've seen this pattern before, with moral panics, fairy tales, witch hunts and other group/herd behavior in people throughout history (and modern times as well).

Yes, I think it's sociological in origin and the UFOs don't exist. There are probably a core group of "true believers" that are absolutely convinced that aliens exist.

Here's an example of a somewhat modern mass hysteria, which started in the 1980s: https://en.wikipedia.org/wiki/Satanic_panic