I was just talking to a professor who interviews applicants to a science-based program. He is just astonished that people mention religion in their application for the reasons mentioned in the OP.
Personally...I would not mention it in a written application. If you must explain a job gap or something like that, talk about volunteering for an international organization that provided training and opportunities to practice public speaking. They'll think you mean Toastmasters. lol.
Then during the interview, if their questions would make you seem awkward and evasive if you don't answer directly, say something like, "I was raised in a fundamentalist religion that focuses on public speaking as a major part of its ministry. As a scientific thinker, I did not believe the doctrine even then. When I was old enough to choose for myself, I left that group."
I don't see why you'd have to name what religion.
Don't linger on it too long--just provide a short explanation and then don't ruminate on it. Otherwise it's going to seem more important than it is.
Good luck.
