Why is the hateful Obama/Joker poster considered news?

Lots of outlets are treating as news the mashup poster with the blaring “Socialist” banner printed under a white-faced Obama, which has been spotted at a single outdoor location Los Angeles. But as I read the dispatches I'm hard pressed to figure out why hateful propaganda is considered newsworthy.

I don't recall the news media dropping whatever they were doing in order to report whenever (anonymous) critics created anti-Bush posters. And if posters of Bush in blackface, or dressed up at Hitler, had sprouted up on a city street, would the press have treated that as breaking news?

This is as close as ABC News gets to justifying its coverage [emphasis added]

The Obama-Joker poster, with the word “socialism” in bold, dark letters printed under the image of his face, has caused a stir on the Web and was linked prominently on the Drudge Report.

Behold your liberal media.