I believe the majority of people in Quebec can speak both English and French so there is no problem with communication with other parts of Canada, I believe that if the citizens are perfectly fine with having French as the official language then I se no problem with them have it as such.
Yes, I do think that they are just in having their official language as french, since there is a really strong feeling of french culture that is still in quebec, and that they need to go ahead and embrace the frence culture that is still there in there territory today.
While not everyone may agree, the consensus is that Quebec wants French to be it's official language. That being said, it doesn't seem at all reasonable to prevent this from happening. If this is the language that the people speak and feel comfortable with, then they are entitled to do as they please.
The Americas were colonized by several European countries and it is okay that some areas kept the language of the original colonizers. For years, in New Orleans in the United States, there was an area that spoke French. We don't need official languages. Just let it happen organically. It's all right.
My usual way of thinking would be to say that Quebec is part of Canada and should have the same language as the rest of the country. But Quebec is very French in culture and the tradition has gone on for so long that it would be almost impossible to change the official language.