Journalism's evolving standards

A telling quote from the Okrent-Krugman wars.

On 6/8/04, I made a numerical mistake, reading from the wrong line in a table of tax rates during the Reagan years. Although the mistake didn’t change the column’s conclusions, I reluctantly issued a correction. But I forgot to use the word “correction,” which I hear got Mr. Okrent upset.

Now since Krugman admits that he made a mistake, innocent or otherwise, why was he "reluctant" to make a correction, or whatever he wants to call it?