… because it is really about resisting the attempt to police belief through the created, colonial category of religion:
Like Herbert, Locke thought he was uncovering the timeless essence of religion. Obscured by this rhetoric is the fact that both herbert and Locke in the seventeenth century were witnessing and contributing to the rise of a new configuration of power hitherto unknown. The advent of the modern state, with its concept of sovereignty and its absorption of many of the powers of the old ecclesiastical regime, was proving that the boundaries were anything but fixed and immovable. The relationships between church and civil authorities were complex and constantly shifting throughout the centuries of Christendom. As for the contrast between religion and civil interests, we can go further and say not only that the boundaries shifted, but that there simply was no such relevant contrast before Locke and others invented it. The very claim that the boundaries between religion and nonreligion are natural, eternal, fixed, and immutable is itself a part of the new configuration of power that comes about with the rise of the modern state. The new state’s claim to a monopoly on violence, lawmaking, and public allegiance within a given territory depends upon either the absorption of the church into the state or the relegation of the church to an essentially private realm. Key to this move is the contention that the church’s business is religion. Religion must appear, therefore, not as what the church is left with once it has been stripped of earthly relevance, but as the timeless and essential human endeavor to which the church’s pursuits should always have been confined.
William Cavanaugh, The Myth of Religious Violence, 83.