It indeed does have to justify to you and to the Canadian public.... However, I would make the point that your legitimacy as a legislator in representing Canadians is every bit as great as that of any provincial legislator. The federal government does have responsibility, for example, for the protection of the border and the protection of federal facilities, which were under challenge during these blockades.
There is no veto given to provincial governments in the declaration of that national emergency. They must be consulted, but if it's an emergency that extends across the country, it's a decision that the federal government makes, ultimately.