This is the guy who admired Hugo Chavez’ dictatorship. And said a few years before Fannie Mae and Freddie Mac failed that they would NEVER FAIL.
He is a fool who loves dictators and will excuse them by any means necessary including lying. And he may be an idiot who got promoted because he was a statist toady. Whatever he says, the opposing is probably true.
The fact that he teaches at Columbia shows how low their standards are.
Here is a good summary:
https://reason.com/blog/2017/11/30/bitcoin-joseph-stiglitz-crypto-outlaw