GoodbyePorkPie, here are a few quotes from the Wikipedia article:
"It is frequently stated that the 1967 referendum gave Aboriginal people Australian citizenship and that it gave them the right to vote in federal elections. Neither of these statements is correct. Aboriginal people became Australian citizens in 1949, when a separate Australian citizenship was created for the first time (before that time all Australians, including Aborigines, were "British subjects")."
So just to be clear, Aborigines were not legally classed as animals, they were British subjects until 1949, then Australian citizens.
"Section 127 was wholly removed. Headed "Aborigines not to be counted in reckoning population", it had read:
In reckoning the numbers of the people of the Commonwealth, or of a State or other part of the Commonwealth, aboriginal natives shall not be counted.
This section should be read in conjunction with Section 24 and Section 51(xi). The section related to calculating the population of the States and Territories for the purpose of allocating seats in the lower house of the federal parliament and per capita Commonwealth grants. The context of its introduction was to prevent Queensland and Western Australia from using their large Aboriginal populations to gain extra seats or extra funds."
From what I read, counting Aboriginal people in the census has been really important in a wide range of social improvements for them, so it's shameful that they were omitted for what appears to be financial reasons. I can't see how it equates to them being treated as slaves though.