When supposed alien craft scour the landscape, sometimes landing (in the old days anyway), or abduct people, what do they obtain?
Aliens, via UFOs, check out military establishments, but not the Pentagon or NATO headquarters. They scan military bases or remote military fields; they don’t even peruse, and never have, military engagements, such as World War I, Korea, Iraq, et cetera.
When alien beings kidnap (abduct) human beings, they always take the non-intelligentsia.
If alien beings have the ability to transport through walls, and abscond with people, why don’t they intrude on museums and take some of the great art works of the world (as Alexander, the NAZIs, and other militarists have)?
Why no theft of the works of Shakespeare, Beethoven, or interest in the pyramids or the Golden Gate Bridge?
What is the benefit of soil samples? Or cow udders? Or the innards of Travis Walton or Betty Hill?
Either alien visitors are without culture, or are interstellar cretins – if they exist at all.