Why were developments of religion and government also "agents of conquest"?

Throughout history, religion and government have been used as oppressive forces, either to expand an empire, dominate a rival, or establish social control.
During the age of colonization, Spanish monarchs famously led the forced religious conversion of the indigenous peoples of Central and South America. By converting these people to Catholicism, it became easier to exploit them and absorb them into the growing Spanish Empire. The Spanish Inquisition is also an example of religion serving as an "agent of conquest." The presence of Muslim Moors on the Iberian Peninsula and the rise of non-Christian faiths was a threat to the power of Catholic monarchs Ferdinand II of Aragon and Isabella I of Castile. The subsequent regulation of religion resulted in the persecution, torture, and death of thousands of people who were deemed heretics.
The age of European imperialism demonstrates how government can serve as an "agent of conquest." A large, powerful government has the capability to mobilize troops, invade a territory, and suppress any opposing parties with ease. England, for example, expanded its empire greatly with a skillful manipulation of public administration. The English government organized several invasions, including North America, India, and Australia.

Historically, the use of religions were used as a form of social control for practical reasons. Religions are cheaper than armies and produce a symbiotic balance between state and cultural objectives. It is important to note that while religions are man made( and humanly advanced), their doctrines or tenets of faith that they advance may not be. This combination of doctrines and politics have on occasion served political agendas.
An example of this use of religion to advance the idea of agents of conquest is modeled by the English king Henry the VIII, who created a religion to support his political ambitions. As the British empire developed and spread around the world through trade and conquest, so too did the Anglican Christian tradition, the official religion of the British empire.