Please correct me if I am wrong, but if you have the parking brake set while waiting out a delay, you can engage in conversation normally...
It is a shame to see a self-induced incident. My only real problem with what they did prior to takeoff was not taking the time to get back into the game after the delay. Once they started moving, the conversation should have stopped, and they should have double checked all settings. I have had more almost-f'ed-myself moments following a ground hold than any other time. You really almost need to start your flight over from the beginning, as if you were at the gate. We are creatures of habit, and a ground delay often forces us to break up our normal flow. After a few missed items under similar circumstances, I now take the last five minutes of a delay to go through the flight plan and the FMS pages, and read the departure pages again.
I know people will be critical of the phone calls prior to getting the actual situation under control, but in all fairness the captain said he did not know what to do. Making at least one call could be seen as a positive step towards ensuring everyone's safety. That said, he ended up getting too wrapped up in the calls and seems to be unaware of most of what was going on in the cabin and outside.
Good judgment comes from good experience, and good experience comes from bad judgment. Lets try to use the examples of bad judgment in this case enhance our good experience and good judgment. I would rather learn from everyone's collective mistakes than make all the same mistakes myself down the road. Everyone made it out of this one ok, so lets skip the personal attacks and harsh criticisms, and point out specific things we can learn from.