For what it's worth, here is a link to a much longer and more detailed version of the story from a website called
PhoenixNewTimes.com
Three US Airways Flight Attendants Are Paying the Price for Speaking Up When They Thought Their Plane Was at Risk
If I am reading this correctly, the airline and union are not supporting the F/As because of "willful misconduct" on their part. In short, after they could not get the F/O to agree to de-ice, they lied to the pilots, telling them that the pax were concerned about the ice on the wings. Only then did the flightdeck agree to de-ice. That lie appears to be the "willful misconduct."
The story says the F/As first reported the incident to the company, after landing; company called FAA; FAA investigation was inconclusive; F/O now suing F/As for defamation.
Something about this story does not pass the smell test, but since we only have press reports like this to go on, I can't figure out where the bad smell is really coming from. Apparently the F/O is not making any public statements, so who knows...