> It will never be necessary to levy taxes to pay for asteroid defense, because I have perfect certainty that no asteroid will ever head toward the earth, so I don't need a moral philosophy that weights taxation against unprotected asteroid strikes.
You can't generalize to an argument against all public spending.
That's the point: the anti-taxer's error is to so tenuously double down on believing they can explain away any public goods problem by saying it doesn't happen in practice. Asteroid defense is just the most extreme example.
It is a similar error to double down so hard on torture never being able to elicit truthful, reliable information.
> It will never be necessary to levy taxes to pay for asteroid defense, because I have perfect certainty that no asteroid will ever head toward the earth, so I don't need a moral philosophy that weights taxation against unprotected asteroid strikes.
You can't generalize to an argument against all public spending.