The only thing I think about on why the Canadian government do that is because they want to ask taxes on cryptocurrency activities that's why they are asking the information of the traders so that they can validate the income of individual and can ask some bigger taxes on the users.
When government do ask out about handling over those clients personal data then all of the possible reasons can be tied up neither on taxation or in AML.
Platforms cant do anything about it when government do require such things and this isnt a surprising thing because government will really find a way or hole
to know to those people who are earning that much and tends to hide via crypto and since they do already have the idea on how much a certain individual can
possibly generate then their concern would be on taxation purposes in most of the time.It wont be surprising if other countries would do the same step.