There was no Aboriginal nation. There was a land with hundreds of scattered tribes of indigenous peoples - who themselves migrated from Southeast Asia. The nation commenced on January 26 1788, when colonisation was proclaimed - in accordance with the WORLDWIDE laws of the time.
There is an expectation of guilt - as we have National "Sorry Day" thrust upon us.
The movement to change Australia day, Sorry Day and other protests are racist and divisive, as is any law that places more rights to some over others. It seems that whatever we try to do to be inclusive and better the lives of the indigenous it is never enough.