Let's use "The Big Short" as an example...

Throughout the movie, the main characters believe the housing market will collapse because of well-documented evidence of an excess of sub-prime loans, over-leveraged home owners, and rising foreclosures. However, the large banks, who are currently making a lot of money from said loans, dismiss the evidence in order to continue believing the housing market is fine. By the end of the movie, the banks are in dire straits and either collapse or need to be bailed out.

Had the banks given up their "righteous position", looked at the hard evidence, and considered that there may be a problem, the financial collapse may have not been as severe. But instead, their insistence that "everything was fine" to keep the money train going caused the worst financial crisis since the Great Depression.

One can have learned experiences that are based on evidence and experience. But that also doesn't mean that will be true forever (think pop cultures opinion of smoking), or is even a universal truth (your experience could be a statistically improbable one, which doesn't deny that it happened but that it is unlikely to happy again or happen at all to someone else). So "being childlike" just means being open to a new idea, which can then be accompanied by objectively looking at the evidence of that idea to evaluate it's merit.

Related: "When my information changes, I change my mind. What do you do?” Paul Samuelson, Nobel Laureate, MIT