Interesting to see the entrenched positions on this. I can fully understand pax getting annoyed and yes, having information on why there's a delay goes a long way to calming the situation. I've seen the monitors at the RYR gates at STN where they're obviously on automatic and make no allowance for late flights, just cycling over at pre-determined times. However, the crew and ground staff are not to blame for the foul-up so complaints should be delivered politely (the same is true of most places, the person you deal with is not at fault and will be more receptive to your complaint if you're polite).
A couple of weeks ago I was on a Delta flight from SFO to SLC and one of the cabin crew failed to arrive. We couldn't board because I assume an RJ700 requires two crew in the cabin for that to happen, but this was explained to us, along with the fact that they were trying to source a replacement. Then we got told one had been found and he was on his way. He got a lot of thanks from the pax as we boarded and again as we got off.
I can fully understand why the crew of the flight under discussion didn't want to fly, good for them and I hope they get a chance to make their side of things clear to the media (probably unlikely, management will sit on them) so that credit for the day's events can be delivered to the correct place.