What you're missing is that anytime you are measuring in seconds or milliseconds from the epoch - that is always in UTC.
So your sydneyDateTime
and newYorkDateTime
may have different zones, but since they are both originating from the same aRandomTimeSinceTheEpoch
value, then they both occur at the same exact moment. Thus neither is before the other.
By analogy, it's like asking which is greater, 1 inch or 2.54 centimeters?
From your comments, it looks like you would like to compare the local times in each time zone, which you can do like this:
if( newYorkDateTime.toLocalDateTime().isBefore(sydneyDateTime.toLocalDateTime()) )
Note that if you are always starting from the same source instant, then this value will always be true. Just like 2.54 is always greater than 1.