You make good points, but they have little to do with the law passed in this case. A note at the bottom of a card stating a "country of origin" has very little meaning, for the reasons stated. However, if you are concerned about the aircraft you fly on, there is more than enough public-source information available to determine whatever you want to know, in far more detail than can be printed on a card.
I understand your concerns about the Airbus 300 and the CRJ, but saying "Made in France" or "Made in Canada" will not add appreciably to your knowledge, especially given as little as the phrases actually mean.
It was directed at the response to the law; the response from the self-appointed high priests that exist in every profession. A rejection of the idea that is much too common today: That the consumer is an idiot, and should rely on "us high priests" to decide what is or is not important enough for you to know.