I can be more specific.
It's a matter of jurisdiction. Jurisdictional powers are enshrined in the Canadian Constitution, which spells out the areas of activity for which each level of government is responsible.
Here we have one element that appears to be controversial from a jurisdictional standpoint. I would think that, if the Department of Justice subjected proposed legislation to a charter compliance test, as part of the drafting process, it would also have a test for constitutional compliance.