I can start answering this question, but it is not for me to argue for one policy or another. It is up to the department to do so.
As I said earlier, pricing theory based on the internalization of externalities is well understood by economists, experts, and even the Supreme Court of Canada. It is necessary that pricing be sufficiently high and applied across Canada to have an impact on Canadians.
Departmental officials may be able to provide more explanation.