You are missing the point. Jumping from the first possible explanation to the most extreme "solution" without stopping anywhere in between is the same thing as not bothering to study, investigate or consider other possibilities prior to making the call that an alien craft was responsible.
So by that logic all unsolved crimes could have been committed by aliens?
"Well sarge, we've ruled out all our usual suspects"
You have not provided any examples where any ufologist has simply jumped to an alien coclusion without first studying the case and considering mundane explanations ... this is the "stopping in between" that we are talking about.
A sometimes token and usually non existent "stopping in between" which constitutes lining up a row of strawmen and systematically knocking them down isn't really helping in regard to reaching the conclusion of "aliens dun it"
As has been pointed out to you countless times; It is impossible to rule everything out leaving 'aliens' as the
coclusion because it would involve being able to rule out things you (and I) can't even think of.
Here is my response as a ufologist to the example you gave:
The Washington UFO flap of 1952 was heavily investigated. Those ufologists who believe that alien craft were involved stopped at several "points between" before arriving at their conclusion. For example were the glowing balls of light that the USAF pilot watched as they encircled his jet simply birds? ... Radar reflections? ... Balloons? ... Airplanes? ... Flares? ... Celestial phenomena? ... Hallucinations? Do any of these explanations fit the descriptions of these objects or phenomena? The answer is no.
How do you know the answer is no? What does an hallucination look like?
The rest of your list is made up of those strawmen I just told you about.
So what were they? Several possibilities have been considered and eliminated.
And many many many many many more haven't even been considered.
Could they have been alien craft? Yes.
They could also have been unicorns or witches riding broomsticks, I didn't see you rule out those two options yet.
But somehow that doesn't stop you UFOlogists from concluding "it woz aliens"... which was kind of my point in the first place. Most sensible folk would conclude they had seen something odd that they couldn't identify, only UFOlogists spin it into a yarn about alien in flying saucers.
Does that mean they weren't alien craft? No.
Do you know an argument from ignorance is yet?
What other reasonable explanations are there?
Perhaps you can tell us?
Well aliens in flying saucers is
not a reasonable explanation for starters.
If we already had evidence of aliens in flying saucers it would be more reasonable, but to posit something that there is no evidence of the existence of as a solution to a mystery is the exact opposite of reasonable.
As for what my reasonable explanation would be; well "I don't know" is OK with me, but if pressed "A series of unrelated events and circumstances with mundane causes being conflated as a single UFO event" would wrap it up until someone actually provided evidence for anything else.