Even though I can't really understand the logic of this person and think they are obviously wrong and a poor troll, this bit

No he doesn't

If that's what you believe than so be it.

I think this is a good way to respond to 'no it's not', he does go more than a bit bonkers here though

If you count yourself as Australian but you're not native to australia aren't you basically in the same boat as the girl tweeting? No, because my ancestors didn't immigrate to Australia, they settled it (or invaded it if you so prefer). Maybe if people of her race invaded Britain and became the majority then I would consider her British, but as of now I would definitely not consider her British. The situation in Britain and in Australia is completely different.

Full disclosure I may have some stake in this and this post is almost pure bullshit. Even by his own standards (which are bonkers) immigrants to the UK and their children may have more of a right to be called 'British' than Australians (or a grater percentage of them do). iirc by 1868 about 160,000 people were basically forcibly transported to Australia from Britain, the population of Australia at the time was about 1 million and it was mostly outside the penal colonies, but forcible transportation (of petty criminals and political prisoners not serious convicts) amounted to maybe 16% of the population at the time, which means that a significant number of Australians are the descendants of people who really didn't want to go there. This is not true of the bulk of 20th century immigration to the UK, a lot of whom came in waves of immigration from Ireland and people who were invited in in the 50s and after from India, Pakistan, the Caribbean, Italy and other places because of (at least what was perceived as) a labour shortage and came here voluntarily. This is total balls though and nobody cares.