Horse 2218 - Why Continue Celebrating Invasion Day?

I currently live in an local government area of Sydney, which is named after the place where the aboriginal people were sent by the fledgling colony of New South Wales because they were seen as a nuisance. Sydney was the first settlement, Parramatta the third, Toongabbie the third and Blacktown was most likely the fourth.
The name Blacktown is literally named for the place where all the "blacks" should be sent and despite some complaint from the local aboriginal peoples who remain, the name still stands as blunt and harsh as it did more than 220 years ago.
Yet this is just one of many aggrievances which continues to remain upon this country; with the most visible being the 26th of January, which carries the name Australia Day even though it is not the day of commemoration of the founding of the nation, and it is the day which many aboriginal peoples proclaim as Invasion Day, when their sovereignty was officially destroyed.

I think that Australia Day is unique in the world in that it is the only holiday which commemorates the putting down of one people as opposed to the founding of a nation. The nearest equivalents that I can think of are VE Day which marks the end of the Second World War in Europe and VP Day which does the same for the end of hostilities in the Pacific but like Armistice Day, I don't think people ever actively celebrated the defeat of Germany or Japan as an ongoing holiday and certainly some 70 years later nobody does. Those days mark the end of hostilities but Australia Day does precisely the opposite, it marks the beginning of antagonism. I know of nowhere where June 28 which is the day that Gavrilo Princip shot Franz Ferdinand is celebrated; not July 28 when the Austro-Hungarian Empire declared war on Serbia.

January 26, 1788 is the day when the Royal Navy who were acting in a military capacity, stole a continent through the cunning use of flags. Later on, the courts would invent the fiction of "Terra Nullius" which said that was nobody living here and that made it all nice and legal. This does of course rather neglect the fact that there were people here but since they didn't have a flag, they didn't count. "No flag, no country" - that's the rule which we've just made up.
A couple of centuries later, it is impractical to deport literally everybody who is descended from anyone who arrived after 1788, for that would mean sending back almost 23 million of us. That's neither practical or helpful. Such a suggestion would naturally be seen as ridiculous but the idea that we should continue to commemorate an invasion is not seen as ridiculous and should be defended, persists; much to my incredulity.

If we take the kindest possible reading of the set of instructions given to Captain Arthur Phillip in 1787, before he left England then although we still find an imperial power who openly has no regard for whatever sovereignty of the native peoples that they might find, we see a curious instruction amidst an open invasion plan.

http://www.foundingdocs.gov.au/resources/transcripts/nsw2_doc_1787.pdf
You are to endeavour by every possible means  to open an Intercourse with the Savages Natives and to conciliate their affections, enjoining all Our Subjects to live in amity and kindness with them.  And if any of Our Subjects shall wantonly destroy them, or give them any unnecessary Interruption in the exercise of their several occupations.
It is our Will and Pleasure that you do cause such offenders to be brought to punishment according to the degree of the Offence.  You will endeavour to procure an account of the Numbers inhabiting the Neighbourhood of the intended settlement and report your opinion to one of our Secretaries of State in what manner Our Intercourse with these people may be turned to the advantage of this country.
- Governor Phillip’s Instructions, 25 Apr 1787

Now you could argue all you like about the merits of signing a peace treaty with the first peoples of the land (I think that in general, the people who argue the loudest against such a proposal are racist and should be told as much) and who it should be signed by, before you begin to argue about what such a thing should contain but in keeping with the original instructions given to Captain Arthur Phillip, then the biggest "kindness" thing that can be done in the spirit of amity with the native peoples of this land is to abandon the 26th of January and replace it.

Why not pick 27th of May, which was the birthday of Henry Parkes, who was the "Father Of Federation" and who probably did more than any other person to actually bring about the Commonwealth of Australia as a thing? Why not pick the 27th of August, which was the birthday of Don Bradman, who probably did more than any other person to bring about feelings of patriotism for the country?

Besides which, in real terms, Australia Day isn't a celebration of Australia. As it marks the day which the First Fleet landed, bunged a flag in the continent and yelled "mine!", it marks the beginning of the colony of New South Wales and specifically the city of Sydney. Australia didn't come into existence until 1st January 1901 but that's already New Year's Day; so it seems to be that the only reason that this "Australia Day" persists is because people just want a public holiday and that's an incredibly weak justification for its continued existence.

Henry Parkes, the then Governor of New South Wales, was reluctant in 1888 to say what, if anything, was being done for Aboriginal peoples to mark the centenary of the colony. He replied "And remind them that we have robbed them?"
If the Father of Federation thought that marking the 26th of January was a bad idea, then why do we persist? Why can't we just vacate this date and have 2017, the last official celebration of theft and invasion?