No, you're not clear on your understanding, that site isn't run by credit card companies, it's run by the three credit bureaus.
Basically, credit card companies (and insurance companies) buy consumer data from the credit bureaus to send unsolicited offers. That site is for you to register with the bureaus that you don't want your credit report sold in that way. That's how come companies can still send you unsolicited credit offers when they already have your information from elsewhere, such as from your bank account or frequent flyer account.
I don't know which, if any bureaus operate in Canada or how that are allowed or not allowed to sell your data. That particular site gives you specifics information about American law (FCRA), and how things work in America with credit bureaus information sharing - it's completely irrelevant for Canada.
Basically, credit card companies (and insurance companies) buy consumer data from the credit bureaus to send unsolicited offers. That site is for you to register with the bureaus that you don't want your credit report sold in that way. That's how come companies can still send you unsolicited credit offers when they already have your information from elsewhere, such as from your bank account or frequent flyer account.
I don't know which, if any bureaus operate in Canada or how that are allowed or not allowed to sell your data. That particular site gives you specifics information about American law (FCRA), and how things work in America with credit bureaus information sharing - it's completely irrelevant for Canada.