The Dutch transfer out of Canada is minimal and pretty much a token amount. Most gold has been transfered out of the USA.
As for why, the American people elected Donald Trump for a second time and the recent trade wars have helped spread the notion that maybe the USA cannot be trusted by its supposed allies as much as it once could be.
It's a bizarre headline.
New York: 31.33% -> 18.52%
Ottawa: 19.72% -> 18.52%
My guess is the original title focused just on the U.S., but the editors didn't want to draw attention from the big cheeto, so the headline was changed and now it looks less like the U.S. is the primary target.
Honestly, if quick access to their holdings is a concern, I wouldn't hold it against the Dutch if they moved more gold out of Canada too. Unfortunately, you presently just don't know when a sovereign nation in the Americas might be embargoed by the U.S..