Louis Riel was the founder of the province of Manitoba, my home province. Thomas Jefferson talked a good game about freedom in the Declaration of Independence, but he was a slave owner. He’s still honored in statutes and coinage because he helped found his country nonetheless. Similarly, Riel is recognized as an early founder of Canada despite his ill fated end.
Manitoba was initially inhabited by aboriginals, French settlers, and the mixed race children between these two groups called the Metis, of which Riel was one himself. The province was founded with the idea that these cultures have a place to call home, but rapid encroachment of English speaking Canada thanks to the newly constructed railway cast that future in doubt.
So his little rebellion in Saskatchewan years later was out of his experience of how Manitoba came to be taken over by English interests and he did not want to see that territory suffer the same fate as the railway made its way towards the Pacific coast.
He did fight a losing battle against Canada, I will not deny it, and he was a bit of a megalomaniac in the end, but he was fighting for a dying French and native culture that lived in those lands against overwhelming encroachment.
It doesn’t rise anywhere close to the succession of entire States and declaring war shortly after in the interests of preserving lifelong slavery for an entire race of people.