Look, you have a little sympathy from me, but dozens of threads over the last three years all stating that CBSA is playing their own game, by their own rules, and that you enter it at your own risk, what else were you expecting? To make it clear, they are not using the Criminal Code as the basis for their regulation, they have used their power to create guidelines to do this on their own. This is how they work, they are not beholden to the standard judicial and parliamentary chain of power. The parliamentary ruling only addressed what they could address, its my understanding that parliament had little power within that situation. How it was handled didn't help, but its outside their purview regardless.
Anyone sending any knife over the Canadian border is taking a risk. Trying to use the law to your advantage will not work because CBSA is not beholden to the law. Every attempt to reign in the powers of the CBSA has met with limited public support, even the latest one. Even when they were grossly in violation of the Canadian Charter of Rights and Freedoms, they mumbled something about security and everyone sort of lost interest.
Until you zoom out to a much wider view, this will always seem silly and illogical. If however you look at knives as an inconvenient consequence of the wider system, and an accident rather than malice, then it starts to make a lot more sense. Not at all in a conspiratorial way, when you look at how powers, responsibilities and limits are divided up in Canada then the CBSA's weirdness makes a lot more sense.