The proscription of 574 was not a sudden act, and the process that produced it is better documented than the ban itself. From 567 a former monk, Wei Yuansong, submitted memorials arguing that the true assembly of the Buddha is the whole realm and needs no separate institution to house it, and that monasteries, ordination and clerical exemption should therefore be dissolved into the ordinary population. From 569 the court held a series of assemblies at which the merits of Confucianism, Daoism and Buddhism were argued before the throne and ranked.
The emperor commissioned assessments. One of them, a report on Daoism, survives as a hostile catalogue of the inconsistencies and borrowings the author found in Daoist scripture; its Buddhist counterpart was produced in the same exercise. The framing question was practical: which of the teachings, if any, should the state sponsor as it prepared to unify the north and then the whole country. The answer arrived at in 574 was neither of them.
The ban was accordingly even-handed in form, striking Daoist establishments alongside Buddhist ones, which distinguishes it from the later Tang persecution that spared Daoism. The reasoning was fiscal and political as much as doctrinal. A monastic population is exempt from tax and from conscription, monastic land is outside the register, and a state preparing for a war of unification wants both. The emperor was also plainly attracted to a Confucian account of the state in which the ruler mediates between Heaven and the people directly, without an independent clergy standing between them.