First, you're right - he's fighting the wrong battle with regards to the field of economics. The Chicago School is most definitely Not the Austrian School, and I think much of the field of actual economists would agree that market fundamentalism is wrong.
But I don't think this is a real attempt to rebut the field of economics itself - this is fundamentally a political piece. Soros isn't an economist - he's a smart guy, he's a savvy investor, he's politically and philosophically acute, but he's not an economist. What he's attacking are political philosophies, not economic theories, and at this point, the ghost of Hayek casts a longer shadow in politics than economics.
Maybe it's been happening for a long time, but the horseshit that's being peddled under the brand of economics in political circles is a big problem in the current political environment, and much of it derives from a fairly easy-to-understand set of works that pushed the market doctrine. He's arguing against bullshit economics, not actual modern economics, even if he doesn't know it.