It had already been mentioned that preconceptions are filters for perception. What a given person can perceive is intrinsically tied to what that given person knows or think to know about the world, his/her experience, or in other words what a person can perceive is a reflection of what that person is: perception is projection.
That is why when anybody is talking about “facts” there are always interpretations involved. Any kind of “facts” will be seen through that person perception filter.
Anomalies studies are a perfect subject where this subjectivity interpreting reality is clearly seen.
What is a “fact” for some people it is not for others: For example some people still think that when an object is not visible to naked eye but visible in infrared in daylight the object is “cloaked”, that is a “fact” for them. But for others that know the effects of the sky scattering of visible light that is simple masking since the stars, planets and many mundane objects are also subject to that masking in daylight. What the given person knows or think to know determine in this case what is a “fact” or not.
Another case where this is clearly seen is with the many anomalies that have tethers, or are similar to balloons, even this previous description is fully depending on interpretation, for many people that is not a “fact” because anything in the air with a tether will be a balloon, again perception is projection.
For many nuts and bolts UFO/ET believers/cultists there is a government coverup hiding the “truth”, that is a “fact” for them. But for others these same believers are really the ones doing a coverup and damage by actively suppressing the reality of anomalies, that is a “fact” for this second group.
There are not “clean” facts or “unbiased” descriptions, anything will be seen and described through the given person perception and “language”, even the language used in describing something is a reflection of who the given person is.
We can not escape who we are, we see the world through ourselves. Perception is projection.