Because many people do not take the time or energy to admit they made a mistake.
Sometimes due to pride or other forces of their mind.
And for the record I have seen a few of the people who have spoken so far, maybe not directly face to face, but close enough to understand them and learn a thing or two.
-"If we do not learn at least one thing a day....Our minds turn to stupor"- Kyle Sparrgrove -2005