Media outlets are notoriously loath to admit mistakes. Traditionally, it's only when the lawyers start calling or regulators hand down an adverse verdict that publications fess up to getting something significant wrong. Self-reflection on systematic failures has never been a strong point for an industry immersed in the here and now.
There are notable exceptions, of course. In 2012 This American Life aired a program-length retraction detailing fabrications in an episode about Apple factories, its most most popular to date. And a year after the Iraq War began, The New York Times apologised for its reliance on dubious unnamed sources in the lead-up the war. Even then, many thought the apology too qualified and too late.