One problem with "maybe" answers is that you don't know for sure. The other problem is that you don't know that you don't know. The "maybe" answer gives you a false sense of having a clue when you actually don't.
People would rather say "maybe it's that" instead of saying "I don't know what it is". Could be because we find hard to admit we don't know, could be because it will give us more work, could be many reasons. I don't know why we do it.
We just need to be aware of it whenever we are looking for facts or when we are the ones giving the answers. It is much more beneficial to say "I don't know" rather than figuring out a maybe answer, even when it's true. Because sometimes it is not.