WO - Not all F-35 good news is propaganda. There is reality there, and at least today it can be said that the program is not visibly slipping against the most recently adjusted flight-test schedule.
Neither would I say that ill-informed negative news is worth hearing, any more than ill-informed positive news.
On the other hand, much of what comes out of LockMart is "propaganda" because that's what public relations and advertising largely consists of. It's designed to influence the way that media and the public think about the JSF - which is what propaganda has been ever since it was invented.
After all, LockMart's not going to issue a press release to say "Clearance for training flights delayed until 2013" or "Carrier trials slipped into 2014 after first roll-in tests", both of which have happened in the past few months. Eventually they have to admit it, usually because they're being poked and prodded by a journo or a GAO investigator, or because they're up before Congress.