From A History of Iran: Empire of the Mind, by Michael Axworthy (Basic Books, 2016), Kindle Loc. 2701-18:
The Shi‘ism of the Safavids and the ulema under their rule had from the beginning more than a streak of extremism and intolerance within it, and this tendency was intensified by the religious conflict with the Ottomans. The Safavids from the outset tended to be more earnestly religious than many previous Sunni rulers had been. This is a delicate subject, but it is important to look at it squarely. The Sufis were increasingly out of favor, and intellectual life was channeled into the madresehs. There were always hangers-on and pseudo-mullahs who could attract a following among the luti (unruly youths) of the towns by being more extreme than their more reflective, educated rivals; and the perceived history of persecution suffered by the Shi‘a did not always prompt a sensitivity to the vulnerability of other minorities once the Shi‘a became the dominant sect. Notions of the religious impurity (najes) of unbelievers, especially Jews, contributed to a general worsening in the condition of minorities, and after 1642 there was a particularly grim period of persecution and forced conversions. Orders were issued that Jews should wear distinguishing red patches on their clothing to identify themselves, that their word at law was near worthless, that they must not wear matching shoes, fine clothes, or waist sashes, that they must not walk in the middle of the street or walk past a Muslim, that they must not enter a shop and touch things, that their weddings must be held in secret, that if they were cursed by a Muslim they must stay silent, and so on. Many of these would-be rules (running directly contrary to the spirit of proper tolerance accorded to People of the Book in Islam, and reminiscent of similar ugly rulings imposed in Christian Europe in the Middle Ages and at other times) probably reflect the aspirations of a few extremist mullahs rather than the reality as lived. Conditions would have varied greatly from town to town and changed over time, but they were still indicative of the attitudes of some and appeared to legitimize the actions of others. As authority figures in villages and towns, humane, educated mullahs were often the most important protectors of the Jews, Christians, and Zoroastrians. But other, lesser mullahs frequently agitated against these vulnerable groups.