Apparently, Bush did not understand how Canada can be against something that will protect it from bad-aiming North Korean missile operators who could drop one short of New York or Chicago, if that protection was going to cost Canada nothing.
And now the Canadian government has to somehow get to the point where it does the right thing, which is protect its citizens but not appear to be assisting or even acquiescing to "weaponisation of space".
Weaponization of space is going to happen and there is absolutely nothing Canada can do about it. The same way Canada itself could not weaponize space. It just does not have the resources and whatever is going to happen will happen because the U.S., China, Russia and a few others so choose.