"It can be" that he knows what it is & has no desire to put himself through the scorn, ridicule, & accusations of hoaxing that he would face by making it public.
No good deed ever goes unpunished.
I totally agree with your first paragraph, but your second is why science is utterly useless without philosophy. You are basically saying that anything that cannot fit into a scientific explanation is "user error"? How small minded. I don't agree with a PN Bigfoot, especially if it is leaving evidence that is physical, but denying that there are things that don't fit into a neat little science book is simply ridiculous.