> They wind up creating simulations that just enforce their bias (because they write code that assumes their biases).

Agreed, such simulations can not be used to answer specific questions. Same thing also goes for weather / climate models, not just human economy.

> try to predict the stock market -- this is essentially what you are asking

No, it is not what they are asking. Mistake here is confusing what is called microstate and macrostate [0] in statistical mechanics.

E.g. yes you can not predict the path an individual gas molecule will take around a driving vehicle because it is a highly chaotic system [1]. And the same goes for individual stocks at a specific time. However, that does not mean that air flow simulations are not possible or useless, quite the opposite.

[0]: https://en.wikipedia.org/wiki/Microstate_(statistical_mechan... [1]: https://en.wikipedia.org/wiki/Chaos_theory