OK, I'll give this one a shot. How can you act if "you don't know?" So ignorance is not a basis for action. You need a starting point. This is what makes believers out of all of us. Anything else is less than human.
Or people have a inordinate need to be BSed. It is true in life. Many times I am asked a question where I had no knowledge of the subject asked about. I give the honest answer of “I don’t know.” The questioner, for the most time, can’t accept the answer.
There are things I don’t know. There are things that you don’t know. There are things that humanity doesn’t know. That’s reality. Understanding that we don’t know things has led to an explosion in questions, research and rational study that have got us from where we were 500 years ago to where we are today - knowing a hell of a lot more than we did then.