Gregoire & Larsen endorsed DelBene in 1st, KCDems unsure about Burner

From
The race is on to fill new 1st Congressional District:

….

In an apparent effort to trim the field, Gregoire and Larsen endorsed DelBene, as did the state Washington State Labor Council.

But King County Democrats struggled with their pick.

A subcommittee recommended DelBene and Burner, but then backed away from Burner when a Twitter message she sent in August 2011, while at Progressive Congress, became public. In it, she criticized President Obama during the debt-ceiling debate, writing, “Barack Obama isn’t a bad Democrat — because he’s not a Democrat. He’s a Republican.”

Steve Zemke, chair of the King County Democrats, said the party likely won’t endorse a single candidate because Burner, Ruderman and DelBene each have fans and are running vigorous campaigns. “I’ll say this, they’re not easily scared out of the race,” he said.

Anyone know why WSLC endorsed DelBene? The debates over Burner at KCDems must have been heated.