Maybe true, but I don't think that's the real reason. I think it has a lot more to do with ego and cowardice. (It perhaps also belies a shoot-the-messenger mentality that exists within many major corporations.)

On The Media did a piece a few months ago about how the 1982 Tylenol recall is pretty much the gold standard for corporate disaster PR: identify the problem, apologize, and explain what you're doing to prevent it in the future. It's not hard, but it takes guts. Even J&J itself didn't meet that standard in later recalls. http://www.onthemedia.org/transcripts/2010/02/12/01