> The biological understanding of sex, as Dawkins points out, is that it is a binary of female and male.

It's taken as binary because the biological difference doesn't result in a meaningful physiological difference. That doesn't mean it's "anti-science" to have an alternative take. Consider that "The biological understanding of sex" as used in your comment should logically be understood as "A common interpretation of the biological understanding of sex". It might suddenly become clear that "it is a binary of male and female" as used in your comment is actually an opinion.

Anyway, I'm not deluding myself that this particular legal definition in Australia was not made in response to recent gender politics. It's more likely there for trans people than for a person who is biologically XXY and physiologically male. However, to say that it's "anti-science" to claim there are more than 2 sexes is mistaken. It is, as I said, an opinionated interpretation of a certain understanding of biology. You disagree with this opinion and you are mistaken when you say it is factually incorrect.