Actually, Democrats are cool with it. The fact that the "Bush lied" meme was a lie is immaterial. It was partisan politics all along, and Democrats got what they wanted out of it.
Now we learn that Operation Avarice successfully acquired 400 rockets and a bunch of chemical weaponry from Iraq in 2005 and 2006. See NY Times discovers that Saddam did have WMDs after all.
So it turns out that Saddam really did have weapons of mass destruction, and it was Democrats who lied, aided and abetted by the likes of Jon Stewart.
The "truth" in politics is whatever people believe. Whether it's actually true or not is less important. Jonathan Gruber explained that to us over and over.