DL3 went back to a gate yesterday after just over an hour of taxiing. I was told secondhand that the crew announced they spent so much fuel taxiing that they needed to refuel.
I have a hard time believing that with every aircraft at JFK having 2+ hour taxis last night, they forgot to "top off" just one of them. The armchair mechanic in me guesses that the plane had an issue with one of the internal fuel transfer pumps or a crossfeed valve that's not required by the MEL, they were taxiing with only one engine (thus using fuel from only one wing tank) and the weight and balance got all jacked up. If the situation was, in fact, something like this, I totally understand that it's probably a little much to explain to a plane full of passengers already running late at 1am.
As for the self-loading cargo - they were offered water and snacks during the delay, and I was told that the door was opened when they went back to the gate (for well over an hour) but they didn't allow anyone to get off. It then took over half an hour for ground crew to show up for pushback.
As for 2385 - none of this is adding up. Based on everything I can gather from several tracking websites, it looks like the flight was initially delayed about two hours, and boarded from a hardstand from the get-go. It looks like they re-opened the door about two hours later, just before 8pm (not sure if it taxied around during this time) back at a hardstand and was there for about 3 hours. Both twitter timestamps are from after the door closed again around 11pm, so it's tough to tell exactly when the police were called, but there wasn't any significant delay (for JFK) getting to the runway after the second pushback. In no way was this 8 hours on the tarmac - more like 5.
Between the claim that the captain was frustrated waiting for ground crew and DL3 waiting for ground crew, I'm willing to bet the tipping point requiring police came while waiting for the second pushback, ironically likely delaying the flight even further. Still, this was 5 hours at most and I'm inclined to believe that Delta's side that they passed out water and snacks - the whole thing adds up to sensationalism and fake news.