People do not understand that visual hallucinations can happen to anyone when they are sober. Our brains are not perfect machines.

https://www.psychologytoday.com/us/blog/the-asymmetric-brain/202212/new-research-shows-how-common-hallucinations-really-are

Overall, 84.8 percent of the volunteers that took part in the study reported having experienced some form of anomalous visual experiences in their life. More than a third of them (37.8 percent) reported that they had experienced an actual visual hallucination similar to what a patient with a psychotic disorder may experience. When the scientists analyzed the additional questions of whether an experience would agree with a clinical definition of visual hallucinations, about 17.4 percent of volunteers had experienced a hallucination that met these criteria.

And I'm guessing the other 15.2 either didn't remember or didn't really understand the question.

It's even more a problem with hearing things that aren't there or, far more commonly, just hearing something but misidentifying it. The whole EVP thing that "paranormal investigators" are so fond of is all about hearing a sound and just assuming that sound is a voice because of our flawed brains (and flawed ears).

Humans seem to be wired to be like this. That's why pareidolia is a thing.

https://en.wikipedia.org/wiki/Pareidolia