This is a particularly interesting question. Those who cannot even admit to the possibility that those objects have been seen by countless other people presents a dilemma. How do they believe anything from history? Did they personally meet Ramses, Alexander, or even Jesus? Why do they believe those people existed when only a handful of people who lived thousands of years ago allegedly said so; but, don't believe thousands of credible people living in their own lifetime?
All of history brought to us from outside of our lifetimes is strictly based on the faith in the witnesses; and, those accounts originate with very few people.
Outright rejection of the UFO phenomenon reveals, in my opinion, either abject fear, religious misinterpretation, or simple-mindedness.
People did personally meet Ramses, Alexander, even Jesus unless all of history is a lie?.
Outright rejection of the UFO is believing someone or many have seen one no records of any type has proven that as a fact.
They are either paid Deep State trolls or just common pests.