The full flight being served with empty seats sounds normal. They reserve some seats for their Elites and you're not one of them. Plus due to the weather people do get moved from one flight to another quite actively. I was moved three times yesterday morning, so I'm pretty sure at least two of those flights left with an empty seat that a bunch of people didn't want to stay in either.

And the FAs do care if it's delayed. They just don't want to explain to get into a confrontation with a random "American" since they're usually more rude.

Anyways, China likes to give Western carriers priority in these weather and ATC situations. And in turn everyone seems to think CA (or MU, CZ, etc) suck and stuff.