I'm Brian. I'm a full-time police dispatcher and part-time graduate student in the marriage and family therapy/counseling master's degree program at the University of Akron (in northeast Ohio). Before I began studies in my master's program, I earned a bachelor's degree in emergency management. I am an atheist and skeptic. I think I can trace my earliest interest in rationality back to my high school days, when I began critically examining theism (generally) and Catholicism (in particular) while taking an elective religion class called "Questions About God." It turned out the class raised more questions than answers, for me.
I found LessWrong by way of browsing CFAR's website and wishing that I had the money to attend one of their workshops. With that being said, I haven't been lurking around LW proper for very long. Thus, I anticipate it will take some time for me to become acquainted with norms of this platform. However, after briefly browsing around, I get the sense that this is a thoughtful community of people that value rationality. That's exciting to me! I hope to get more involved, as time permits, and to eventually become a valuable contributor.
In characterizing this trend, it seems as though you are assuming that membership in these various communities is mutually exclusive. However, this doesn't have to be the case. For example, a person may be both a Catholic and a leftist. Thus, a good follow-up question might be: To what extent does leftist politics and Catholicism have an impact on a person's evaluation of risk. For example, one could compare Pope Benedict with Pope Francis, who are both Catholic, with each other and potentially conclude that income inequality/exploitation influences Francis' conceptualization of risk to society to a greater degree than abortion or sexual immorality.