Canadian law guy here. The definition that the Canadian International Trade Tribunal of "centrifugal knife" is quite a bit broader than how it has been interpreted in the courts in a criminal law context. You can see a summary of the decision which sets out the definition here:
https://cbsa-asfc.gc.ca/publications/cn-ad/cn18-01-eng.html It is this decision that the CBSA are acting upon when they seize folders at the border.
Basically, any knife that can be opened with one hand is likely to be seized by the CBSA if they inspect it. Also, if you plan to appeal the decision, you will need to understand administrative law in Canada. Common sense definitions, dictionary definitions, hurt feelings or whatever else are irrelevant to making a winning case here. If you don't have a lawyer arguing on your behalf, your chances of success are probably low.
Now I'm obviously a knife guy and think this decision is garbage. However, reading through the comments here is a bit amusing. The brand/country of manufacture/potentially IP infringing design of a folder is irrelevant to the CBSA seizing it as a prohibited weapon. Also, the operation of the CITT and its decisions have nothing to do with politics or the government of the day. The decisions are made by bureaucrats who interpret complex laws and regulations relating to the importation of goods into Canada. Obviously, I think they have it wrong here but my personal feelings don't change anything.
The only way this decision will get changed is if you argue through through the first instance and appeal steps with the CBSA/CITT and then end up at the Federal Court of Appeal. I'm guessing that would take about 3-5 years (and you can guess how I know). You can speak to your MP but honestly, they aren't going to care. You are a person suspected of importing a prohibited weapon and you want them to go to bat for you? Unlikely.
Anyway, this whole thing leaves me feeling cynical but the way around this problem is to only buy folders from dealers shipping within Canada. I wish I had something more hopeful to say but that's basically it.