The Age explains this better than Mr. Heiner does; he “signed away” his (Australian) citizenship. He “signed away his citizenship when he filled in a form to take on post-nuptial Irish citizenship after marrying an Irish woman”.

After having a child with “another partner” on 2011 his application for citizenship for that child was rejected because Mr. Heiner is not an Australian citizen any longer because he signed the right away.

There is no ‘birthright’ citizenship in Australia, and at least one parent must be an Australian citizen for the child to become a citizen.

Given Australian government's slapdash attitude to citizenship for some really bad people, it's hard not to sympathise with Mr. Heiner, since his Australian roots go back a couple of centuries. But, he does have to take responsibility for his personal actions.

"Voters are encouraged to focus on where the line between 'us' and 'them' should be drawn."
- Is it a line or is it a scale?

Is it wrong for me to think that an 'Australian' who was born here, grew up as a child here and went to school and got their first job here and who never had any connection to a foreign place might be 'more Australian' than say an 'Australian' who wasn't born here and didn't grow up here?
- That their 'coming into the world and growing up' 'experience' that shaped who they are is connected to an entirely different nation and place?

- Is being Australian an experience from being connected to this place from birth as a life experience or is it a piece of paper?

And if it's not about being 'connected' to this place, then what do you say to indigenous people?

"Tomorrow it could be an ethnic community, a religious minority, a political movement, or any other class that Parliament, or the electorate, comes to regard as undesirable."

So what if it is?
What if cannibals from New Guinea decided to move to Australia.
You're saying we can't discriminate against them because that might inadvertently discriminate against their culture, just like we let Indians carry ceremonial swords around at schools because we can't discriminate against their culture.

And then you're also saying that we don't have the democratic right to say or decide, 'We should get rid of these bloody cannibals!'

The authors court case seems interesting, as are laws around dual citizenship.