What’s wrong with this correction?

In their September 18 story on the exposure of ACORN by James O’Keefe and Hannah Giles, Washington Post reporters Darryl Fears and Carol Leonnig fabricated the existence of a quote indicating the existence of a racial animus behind O’Keefe’s work. When called on to supply the quote, the Post instead ran this correction:

Th[e] article about the community organizing group ACORN incorrectly said that a conservative journalist targeted the organization for hidden-camera videos partly because its voter-registration drives bring Latinos and African Americans to the polls. Although ACORN registers people mostly from those groups, the maker of the videos, James E. O’Keefe, did not specifically mention them.

What’s wrong with this correction (and the related AP correction)? Gary Larson (not the cartoonist) explicates the text in “Washington Post admits to bogus quote.” Larson’s column provides a disgusting footnote to a disgusting story.