I worry more about the damage it does outside of Quebec. It fuels the rednecks.
I had a guy from Ottawa tell me not to long ago that the French language college at the University of Regina was a result of Quebec language law and federal bilingualism.
He's never been to Regina (I personally doubt he's driven to Hull either) and it was pretty obvious that he had no idea that the college was there to represent French-speaking people of Saskatchewan and ensure them an education that could take them and the province into the future.
When I pressed him on it, I got the standard, "Quebec has that sign law," answer.
Personally I don't care what language people speak. I wish I could speak more than one, other than being able to curse in Cree. I worry more about the loss of regional dialects and languages world-wide than I do about Canada in particular.
I'm just not sure that Quebec is doing itself, or other French-speaking people in Canada, any favours with their law. It limits free speech and gives those who base everything on which language is spoken instead of which ideas are spoken a lever.