If things were a few cents more in Canada I don't think anyone would complain. But most products are SIGNIFICANTLY more, often double. the difference in labelling costs simply doesn't work as an excuse for that.
Unfortunately the auto corporations have a nice racket going with cars, it's illegal for me to go overseas and purchase a car and bring it home (unless it's over 15 years old) Even cars from the USA have to be on a specific list to be allowed in, and it's the manufacturers themselves that decide what cars are on that list, and what modifications you need to do to them (and who is allowed to do the modifications) to be allowed in to the country. They claim it's due to different safety standards, but the standards are so close that it's obvious those standards are only there to be a trade barrier and not to improve safety in any way.