They don't.
A bunch of them did, but, a minority. Only about 25% want it now.
Quebecors are even more different from other Canadians than the Scots are from the English. They are a distinct people, with their own language, laws, and religion. They use the Civil Code that dates back to the Romans, while the rest of Canada uses Case Law, based on British Case Law.
Of course, they have their own language. There is some French spoken outside of Quebec, mostly Acadian French in New Brunswick, and a bit in Nova Scotia. Quebec French is a different dialect, and about 300-400 years different from France French too.
They were also overwhelmingly Roman Catholic, although that changed in the early 1960's.
As a minority in Canada, they felt they could not get their way. And, for a long time, this was fairly true. However, there is a lot of equality now, or, even "over" equality, and, many immigrants, so the original "pur laine" (pure wool) Quebecors with hundreds of years of history in the province have seen their numbers decline. So, there is not the same amount of interest as there was some years ago. For a few reasons: e.g., Canada now accommodates their language, etc., but, as a French speaking state of about 10 million, they would be surrounded by almost 400 million English speakers, who would NOT speak French!