The stigma and low status of Aboriginal people is a factor contributing to family violence and other self-destructive behaviours. Not the only or most direct factor, but a factor none the less. Celebrating the arrival of white people as out national day is one of the symbolic Australian rituals that remind blackfullas of their marginalised place.

Measured experiences of racism and exclusion correlate with lower self-esteem and external locus-or-control which in turn correlate with anti-social behaviour.

Obviously changing the date isn't a magic bullet but it's one easy thing that could contribute to repositioning the status of Indigenous Australian peoples. Of course there are other things to be done and there are people working on the more direct causes of dysfunction. I'm in Indigenous education myself and we've (the particular place where I work) been kicking goals for years.

There's a lot of evidence to back up my claims for correlation. Here's one: Zubrick, S.R., Dudgeon, P., Gee, G., Glaskin, B., Kelly, K., Paradies, Y., Scrine, C. and Walker, R., 2010. Social determinants of Aboriginal and Torres Strait Islander social and emotional wellbeing. Working together: Aboriginal and Torres Strait Islander mental health and wellbeing principles and practice, pp.75-90... if you want more go to google scholar and enter the keywords: "social determinants" Indigenous, Australia, racism, exclusion.