Why seemingly assume a singular explanation for UFOs?

I’ve noticed that a lot of threads on these and other sites, regardless of questions about if any of them are correct, that talk of “what’s going on with UFOs” seem to treat them like a monolith that has “one true explanation” – whether it’s aliens, extra-planar beings, strange or novel natural phenomena, or just the magic of human psychology. The question is, though, why? Why would one assume that something as broad as “an anomalous object or sight you see in the sky and that cannot be identified to anything conventional” would be or have only one explanation? It seems much more likely that more than one thing causes such a broad range of phenomena, which may or may not include more exotic or fantastic elements; and moreover, if those more exotic elements do exist, that they too are likely to have diversity – e.g. I see posts often talking of aliens as being “good” or “bad” which seems really blanket in its own way; I’d imagine that if aliens are visiting Earth you’ll get a lot of types even among the same species – consider how we humans have both scientists and gangsters.

It seems a better approach is not trying to find “the explanation” and “the motive” but rather trying to see how that each individual anomalous report, video, documents, etc. do or do not contribute evidence or at least weight toward these various possible sources, and then after seeing that, whether any larger picture conclusions could or could not be drawn.

Of course, I may be mistaken in this presumption, but it’s just how it feels to me from reading the posts, that everyone is looking for just one thing to “explain it all” and then getting caught up in how that this or that doesn’t “seem to fit”, when from the basic definition of the object of study, one should not expect such a singular “fit” in the first place.