Ok 'valid' arguments (well, its valid in my eyes, but i guess it depends on your point of view) - yes it is difficult when you see lots of indigenous scholarships and you are also struggling financially - however the statistics (census) still demonstrate that:
"Non-Indigenous people were twice as likely as Indigenous peoples to have a non-school qualification in 2006 (53% compared with 26%). Non-Indigenous people were more than four times as likely to have a Bachelor Degree or above (21% compared with 5%) and twice as likely to have an Advanced Diploma or Diploma (9% compared with 4%)" Source:
http://www.hreoc.gov.au/social_justice/statistics/index.html#Heading363
The universities (and the government as a whole) are trying to do their bit to increase education standards of the indigenous population - trying to bring it more in line with the rest of Australia. Until education, health etc of the indigenous population is in line with the rest of Australia it is likely that there will continue to be indigenous scholarships or other means of assistance being provided specific to them.
Furthermore, it is likely that the scholarships are also taking into account the financial needs of the indigenous applicants when awarding the scholarship (ie. if you are choosing between two indigenous candidates and one can afford it and one can't - then reasonableness would show that the one that can't afford it would get the scholarship).
In my personal opinion, when the standards of education/living/health of indigenous communities are equal with the rest of australia, then I think that's the time to be complaining about the unfairness of the scholarship system.