Try to think like people you desagree with. A considerable part of the Canadian population wants the war not only to reclaim Edward VIII legitimate throne, there are more factors to that.
First, they want to get rid of the British, a way to do that is to allow them to recover the island, that is the best way for the Canadians since on other scenarios the British community is going to stay there and be influent.
The second is imperialism, pure and some imperialism, Britain is part of the British empire, the core part, a lot of the Canadians, if not most of them came from Britain on the 19th century (not counting Quebecois), they can trace their grandgrandfather place from locations like Middlesex or Cornwall or Scotland, this feeling takes a long time to go, you can see on Portuguese posts and Portuguese timelines that people still are affected on some way or another for losing Angola, this 50 years after the war, while Britain was lost in 1925 and the game starts in 1936.
A third reason is to countain syndicalism, as the cold war showed people find a legitimate reason to go to war to keep a doctrine they hate under control.
These are some factors that would make most of the anglophone population of Canada support the war. I'm not saying it is right, I'm saying that it makes sense.