So the question is: when did Nassim Taleb cut off economists’ balls?

The article is dated June 1998. His first popular book, Fooled by Randomness, came out in 2001 and contains attacks on Scholes and Merton, so this evolution in thought must have come about very rapidly.

My best guess is that the key event that changed his perspective was the bail out of Long-Term Capital Management in September 1998, orchestrated by the New York Federal Reserve. Scholes and Merton were principals in LTCM, and indeed, Taleb criticizes them strongly for this failure in Fooled by Randomness.

via When Did Nassim Taleb Cut Off Our Balls? | Portrait of the Economist as a Young Man.