Why can't the Washington Post call the “Lie of the Year” false?

In an article this morning on the state of health care reform, Anne Kornblut of the Washington Post noted that Republican National Committee chairman Michael Steele referred to Thursday's health care summit as “a death panel for Obama-care,” and helpfully offered a bit of context on what, exactly, a “death panel” is:

Death panels became part of the debate last summer, after prominent Republicans, including former Alaska Gov. Sarah Palin, claimed the government would set them up to decide who could live or die.

Seems to me that if you're going to go to the trouble of explaining why Steele used the phrase “death panel,” you should also point out that there is no such thing as a “death panel” and that nothing of the sort has ever been proposed. It was invented out of whole cloth by Palin, and it was such an egregious fracture of the truth that PolitiFact deemed it the “Lie of the Year.” The paper's own media critic even highlighted “death panels” as “a point where the media should say a politician is wrong,” and the Post has reported in the past that "[t]here are no such 'death panels' mentioned in any of the House bills."

So why can't the Post now call this wildly false claim “false”?