Early America was anti-Catholic, and opposed the Quebec Act, which among other things, guaranteed free practice of Catholicism, the majority religion in QC. As the French settlers were the only ones living in Canada at the time, they had no appetite to join the Revolution.
Canada has no good reason to exist. By all accounts, the northern colonies should’ve been part of the Union from the beginning. But we have to live with that mistake of history, and Canada is undeniably its own country now.