The reason that is is that purely statistical/predictive models of macro are subject to the Lucas Critique [1]. It says roughly, if you observe an economic relationship is happening, but you don't have an explanatory reason why it is, it's a bad idea to use it for policy prescription.
The NY fed model has a whitepaper here [2], which should be accessible to the technical data scientist (technical, but not prohibitively so).
Their readme points to a few posts on using it, I think the open source code comes with a csv for example input data. There should be publicly accessible macroeconomic data in a few places for you to play with it, say at FRED or the World Bank. I think Julia has a Stata-style api package for FRED data, making the data processing easier.
Have fun!
[1]https://en.m.wikipedia.org/wiki/Lucas_critique
[2] https://www.google.ca/url?sa=t&source=web&rct=j&url=https://...