You may have touched on it right there. People understand that money itself is zero-sum…but they lack the understanding to go just one level deeper and realize that doesn’t matter…as wealth is not. And wealth is what is important. They don’t get past “stage 1” (another h/t Thomas Sowell.)
But I still say the difference between Right and Left / libertarians and statists is the conflict of visions about what man is.
I would sum it up in basically that, the leftists/statists operate under the belief that man is a virtuous creature…and that the only problems in the world stem from the institutions we currently have…and therefore if only we could set up the right institutions, all the world’s problems would all but completely disappear (unconstrained vision). Conservatives/libertarians essentially believe that it is man himself that is flawed, and that therefore there is no such thing as the “right” institutions, because no matter what you set up, it will still be flawed man running them…so there is no solution, just tradeoffs (constrained vision).
But I would take it from Sowell himself. Here’s a short clip where he answers it at the end, and here’s a great interview, which is lengthy, but which you should definitely make the time to watch.