This is true, and yes wfg did imply the threat.

(Now, analyzing not advocating and after upvoting the parent...)

I'll note that wfg was speculating about going ahead and doing it. After he did it (and given that EY doesn't respond to threats speculative:wga should act now based on the Roko incident) it isn't threat. It is then just a historical sequence of events. It wouldn't even be a particularly unique sequence events.

Wfg is far from the only person who responded by punishing SIAI in a way EY would expect to increase existential risk. ie. Not donating to SIAI when they otherwise would have.or by updating their p(EY(SIAI) is a(re) crackpot(s)) and sharing that knowledge. The description RationalWiki would be an example.