The problem is when you finally get away.
No it's not a problem. People should understand that once an aircraft departs, particularly a LH flight, things can change along the way. Arrival at destination is not guaranteed.
I get the feeling here that this CC began to get into their minds early in the piece that they were not going anywhere, were well into planning a night in LA and got a shock when the eventually aircraft departed.
Where to? Well SYD was the plan but like all good operations there were other options if getting to SYD inside of 20 hours wasn't going to happen.
Brisbane, Fiji, Auckland.... Cairns even. Anywhere reasonably close to destination where a standby crew could be expeditiously sent to get the aircraft to Sydney.
If the posts are true about the CC arguing that the aircraft had every right to depart even if they were not going to eventually end up in SYD, then it highlights the fact that they either haven't read the contract they operate under and/or have little idea of how a modern airline works.