I'm another one who had been hoping this thread would fade away...
Regular public transport means that seats are available on flights operated in accordance with a published schedule to the general public. It doesnt mean that they are providing a "public service", merely that where the service is provided, it is available to the public. As it happens, the published schedule appears not to have any flights operating Christmas Day. For flights to be operated to every desired destination on every possible day, you'll be wanting a charter operator.
If there are no scheduled flights to your destination that day, you cant insist that "its a public service" - some routes operate some days but not others, and it seems that no routes will be operating Christmas Day. If Rex arent selling tickets on flights that day, and you cant book flights, thats the business decision made by them. Maybe it will affect profitability, or maybe its cheaper to shut down for the day and let the ops staff, ground handlers, pilots, flight attendants and all the other employees spend the day with their families. Alternatively if it boosts morale and improves staff retention it could be a net positive for the company without incurring the cost of running (potentially, I dont know) lossmaking flights that day? Whatever the reasons, it looks like the Rex staff get Christmas to spend the day with their families and friends rather than chucking bags on a 40 degree ramp or shuttling up and down the east coast!
good on 'em, the more companies that take that attitude and let their employees have one day a year where absolutely everyone gets the day off to spend with family, the better.
Merry Christmas to all!