Before any laws can be produced, communiques written, or any other form of community be established, certain baselines must be defined.
Measurements of time, mass, volume, and distance, and even the definitions of words must all be clarified before everyone truly understands what we are talking about.
For example, we are saying that Ministers are having terms of X years. Well... how long is a year? On Earth a year is 365¼ days, but in space, when a sunrise happens every 6000 seconds, some might call a day the time between sun rises. That would make 14.4 Asgardian days to each Earth day. Do we still hold to the 365 days (again, depending on the definition of a day), or do we adjust our calendar to our new concept of 'days', having over 5000 days per year?
I have seen arguments about helicopters on here that were going on between Asgardians because they both had different definitions of what a helicopter was. Unfortunately, we really do need to be this specific and pedantic to remove misunderstandings.
So, while I understand we have to agree to a calendar, it doesn't mean we need to make up our own. Sure, Westerners might be ticked if we don't use the Gregorian they are so familiar with, and Chinese might be ticked if we don't use the Chinese calendar they are familiar with (despite the fact that the Gregorian calendar is the official calendar of the Chinese government), and gods forbid we don't properly calculate someone's religious holiday correctly or there will hell to pay.