And it would appear many Canadians are ignorant of it too. The War of 1812 was a British victory.
Upper and Lower Canada were part of Great Britain. This place was a colony. Everyone here was a British subject. Children born here were British by birth. The exception to that were natives, who the British did not consider citizens, but subjects, responsible to the Crown.
The country Canada came into existence in 1867, when the colonies here were made a dominion by British parliament.
The War of 1812 was fought between Britain and the US. Yes, there were local militiamen from Upper Canada. But there were also natives and others who came along for the ride. No Canadians fought in the War of 1812 because there was no such thing as Canadians.
Upper and Lower Canada (colonies) were merged in 1840 to form the province of Canada. In 1812, the colony of Upper Canada formed militias, but they weren't Canadian. They were British. There was no such thing as Canadian citizenship. You were a Brit. The units were made up of locals - most of British origin. They would have been farmers, tradespeople, and local natives.
To state anything different is revisionist.
https://en.wikipedia.org/wiki/War_of_1812