As above, what would you call people who take on an objective view, who have seen something they do not understand but are guided by science, facts, evidence...and that are not what you call 'true believers'?
This is sometimes hard to distinguish, as most conspiracy theory believers (of which ufo believers is a subset) justify their belief with evidence and pseudoscience. Metabunk exists to debunk that evidence, to show it doesn't quite do what the believers want it to do.
I learned that lesson in school, ironically not in a science class. We were analysing short stories, the teacher would guide the class to interpret the story, and then I'd raise my hand and go, "but couldn't it be something totally different?" And I had found a few quotes supporting my analysis, too! The teacher would then draw my attention to the parts of the story that contradicted my reading of it. It made me realize that to understand an author, you have to find out where that story, in its entirety, is leading you, otherwise you're mistaking the author's intent.
So a lot of what we do at metabunk is to restore the context of a sighting, to add data, and to discover interpretations that fit the observation more closely and with greater likelihood than what the observer first thought.
There's no shame in thinking, "hey, could this be a UFO?" But it's going down the rabbit hole if you avoid the process of looking for more mundane phenomena that would explain it, and to not accept that "hey, this could be something common after all". Which, to be fair, is something that should always be on the table with the "small moving dot" sightings, once the excitement wears off.
When you see people who thwart this process by withholding data/evidence that wouldn't fit their narrative of mystery, you can be sure that they're true believers, or that they're cultivating them.