Regardless of the date, the same people will do the same protests.
The date is the date in History. You can't rewrite history. What happened, happened. Celebrate it or not, it's a free country so make the choice. Just remember we are celebrating a "freedom moment" and a step forward for most. For those that don't agree you are free to lament the day as invasion day.
I'll fly the Australian flag. I have no problems with someone else flying the aboriginal flag, they just can't use my pole.
National holiday of Australia on 26 January
Australia Day is the official national day of Australia.Observed annually on 26 January, it marks the 1788 landing of the First Fleet and raising of the Union Flag of Great Britain by Arthur Phillip at Sydney Cove, a small bay on the southern shore of Sydney Harbour.Wikipedia