Answer: Because the Liberal Party chose a bloke over two women to be its candidate.

This comes shortly after Opposition Leader Peter Dutton lambasted Woolworths for taking a business decision not to market Australia Day junk this year - you know, tasteless flag-emblazoned thongs, shorts and bikinis, Australia biscuit cut-outs, and rear-window poles to fly the flag.

Dutton said people should take their business elsewhere. Cancel Woolworths, said the politician who has long lambasted cancel culture when it came from the left.

This gives us a flavour of how Australian politics might shape up this year - an interesting development of what American rationalist Steven Pinker calls the "my-side" fallacy.

The my-side fallacy has been endemic in Australian politics for decades. It postulates that voters do not rationally weigh up individual policies or even the totality of policies and vote accordingly - either according to what they think is best for them or best for the nation. Rather, they vote according to whatever the leaders of "my side" say.

In the US, it has been demonstrated to be an even more a powerful determinant of how people vote than, say, the left-right; progressive-conservative; collectivist-individualist splits.

There, under Donald Trump, the Republican "my-side" has changed dramatically in the past seven years - more protectionist, isolationist, authoritarian, and appealing more to rural and small-town people, especially males, with less education. A seemingly unstoppable percentage of voters continue to support Donald Trump as the embodiment of his party even though he perpetuated 30,000 lies while President; supported a coup against the duly elected new President; and has been indicted on at least 90 felony charges on electoral matters and misuse of funds.

So, even if the nature of "my side" changes quite significantly, in the US at least, voters will continue to support it - seemingly irrationally.

How do we explain the seeming irrationality? Because it is rational for people to support their tribe. It was rational to do so on the savannah and to some extent it still is now.

Would it be smart (or rational) for someone at a cook-out in Alligator Bayou, Louisiana, or at a barbecue in Pumpkin Place, Kingaroy, to sing the virtues of electric cars and decarbonisation? Self-preservation - socially and literally - suggest not.

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Is it rational for the same people to take credence from conspiracy theories? Well, yes. Human conduct has always been rife with conspiracies - luring other tribes into death on the savannah or conniving and conspiring to get to the top at work, in corporations and in politics.

Every Liberal leader since Holt has been a conspirator of a victim of conspiracy. The same can be said of Labor leaders since Whitlam.

It would be rational for, say, Qantas employees to suspect a conspiracy between governments, upper management and business organisations and lobbyists to do them out of pay, conditions, and even their jobs.

Which environmentalist would readily dismiss a theory that there is a conspiracy between fossil-fuel companies, government and big business generally to downplay any need to do anything about climate change?

The survival instinct tells you it is rational not to dismiss all conspiracy theories. Social media did not invent the "my-side" fallacy or the generation of conspiracy theories. They have always been with us.

The difference, perhaps, is that pre-internet "my-side" and conspiracy material usually required some later verification, otherwise the purveyor of the material would lose credibility. The sort of credibility, for example, of someone suggesting in early 2010 that there was a conspiracy against Kevin Rudd, and being able to say in June 2010, "I told you Kevin was gone".

So, let's not bemoan the wholesale adoption of my-side fallacies and conspiracies as irrational and deplorable. Rather, let's understand it, and counteract it. Let's ask for verification rather than mindless repetition of doubtful conspiracies and dubious information.

It is quite rational for Dutton to play my-side politics with Australia Day and the Voice, if you describe rationality as acting to get a desired result for yourself.

This is why the human race is marching to planet-wide climate catastrophe.

And why someone like Dutton can assert that a January 26 Australia Day is in "the national spirit", as did the conservative think tank the Institute of Public Affairs when it released the results of its poll that 63 per cent support January 26, "despite the continued campaign of the political class and elites to denigrate and cancel our national day".

A date supported by only 63 per cent cannot rationally be cited as a unifying national day unless you want to rationally exploit the differences by draping the flag, as Dutton is.

Dutton is changing the nature of his "my side" by going some way down the Trump path with the use of the flag, attacking big business and standing up for the working battlers who are interested in the cost of living rather than social causes.

The danger for Dutton is that he does not have an Electoral College with its system of winner-take-all in each state which biases it to the Republican Party.

Dutton's new "my side" constituency - rural, outer suburban, male-dominated, less-educated, older - indicates he has given up on the wealthy, more-educated, professional, inner-urban constituency which delivered 10 Liberal seats to independents and the Greens in 2022.

As it happens, Dunkley is not such a seat, so without some complicated booth-by-booth analysis it will be hard to tell if Dutton's new "my side" is a winning strategy. But it certainly has its risks.

And the conspiracy theories can cut the other way. Would you describe as irrational anyone who put forward a theory that there is a conspiracy in the Liberal Party to hold back the number of women representing the party in Parliament?