In a monarchy, the King is the "cause" and anyone who is loyal to the kings policies (regardless of their affect on the citizenry), is a loyalist, and one who acts against them is a traitor. And obviously it's impossible for the King to be a traitor.
However, in a democracy, the People are the "cause", and the administration is there to administer for The People. If someone is loyal to the "Current Policy", which is destructive to The People, they can be considered a traitor.