Well Ayn Rand's work, which is the basis for the philosophy of many libertarians I know, is also highly fictional...
If they're basing their philosophy on the story, they're doing it wrong.
If the story inspires them to consider the philosophy or they consider it illustrative of the philosophy, that's more like it.
By the way, it's nice that you are happy to pay your taxes if the government spends it well. However, you might want to consider that other people may have different opinions on that or, indeed, what constitutes "spending it well" and taxes are not voluntary.