Zealotry is not confined to religion but appears in any belief domain

Evidence

By the fall of 1993, I had a twelve-item scale assessing this zeal, Exhibit 8.2, which I included in the student and parent booklets just described. The thirteenth question asked the respondents to describe their particular outlook or cause. Notice the numerous possibilities. While being a zealot, like being dogmatic, originally had a religious connotation, I also wanted to find the zealots in the environmental movement, the feminist movement, science, capitalism or socialism, animal rights, whatever. — Bob Altemeyer, The Authoritarian Specter, 2757