There are three kinds of people:
- Those who believe the world is evil and fear what the world will do to them.
- Those who believe the world is good, and want to help contribute to the goodness.
- Those who don’t care.
Which one you are depends on a lot: experience, culture, genetics, beverages, phase of the moon …
If person of kind 1 asks a question, and then realize/find the answer, they may be afraid that someone in the future will find their question, and believe that they are dumb and stupid for asking it. Thus they want to remove the evidence. Or maybe just want to avoid anyone having to do work to answer a question that’s already answered.
If a person of kind 2 asks a question, and later finds the answer on their own, they will post a reply to themselves, saying “oh, wait, here’s probably what it is.” They likely do this to help someone else who have the same question in the future, because Google will find the question and the answer.
If a person of kind 3 asks a question, and then find the answer, they won’t be back, so, whatevs.