An Imperialist at the core must believe that is the right of the Imperial Empire and their leadership to rule with absolute authority. Palpatine during his tenure as Chancellor increasingly consolidated executive power in order to prosecute the Clone Wars in decisive legal action to ensure victory. The Emergency War Powers given to Palpatine was the first true step of allowing an Imperial Empire to truly take hold. An Absolute Dictatorship was installed under the self appointment of title Emperor of the Galactic Empire. Those same emergency powers continued on and martial law was effectively codified into the Galactic Empire and all its successor states that followed suit.
The formation of Moffs was the ultimate projection of Imperialization. These officers were supposed to efficiently govern individual sectors and regions acting as the military governors and head of the government for these areas. In essence each Moff was a warlord granted a fiefdom with loyalty to an Absolute monarchy. The Moff held a broad mandate which allowed them to utilize martial law if needed to when the governments or civilian authorities failed to function effectively. Thus the Imperial military was needed to maintain order, security and provide essential services. A Moff could effectively remove a systems government by a coup d’état if needed. The use of martial law was needed in order to suppress political opposition; stabilize or crush insurrections or perceived insurrections; and also in the case of major natural disasters the Moff could use this tool to prosecute humanitarian operations.
A fact that is often noted by historians is that the Galactic Empire even at its height the use of direct governance of a system was one out of eighty. Thusly the vast majority of systems either remained intact or did nothing to bring the attention of the Regional Governor down on them. A planetary or system culture and sovereignty are respected by the Imperials. As long as their laws and beliefs did not come in conflict with the Imperial Ideology or instigate conflict with neighboring systems.
In this way the Imperial Empire functions as a Parent who knows best, an entity that enforces the most stringent of laws to prevent dire calamity from befalling those whom live under the banner of the Empire.