Does the rest of the world know something the US doesn’t? Obviously yes, which is that the global economy is tipping back into recession in an environment of historically unprecedented financial fragility. Government, consumer and business debt has never been this high, the leveraged speculating community has never been this leveraged, and unemployment in a lot of places is already too high for political comfort. Toss a recession into this mix and the result will be a whole series of possible crises, each more apocalyptic than the last.
So the other central banks are reacting as fiat currency central banks always do, with easier money. The fact that money is already as easy as it’s ever been won’t stop it from getting even easier. As one of the above articles noted, “Denmark’s deeply negative deposit rate illustrated that there was still room to reduce rates.”