Jim, I’m not sure I agree with your conclusion about the best approach. I think the most effective change will come from efforts to persuade the leaders, not the followers. If people feel they are being made fun of, they will get defensive and become further entrenched.
I was raised Catholic, went to Catholic school for 6 years, youth group retreats, catechism, sang in the choir, alter boy to a Cardinal . . . the works - the rest of my family remains staunchly Catholic. But I’ve never rejected evolution (I have never met a Catholic that does), my parish generally encouraged my questioning and searching, and it was this liberal attitude in my church and from my parents that led me to where I am today. In fact, if there were people on the outside pressuring me, I would probably have been more resistant to the natural process of losing my faith through application of reason. If someone had attacked my church or had tried to mke my pastor look foolish, I would have defended my church and my pastor - even if I thought my pastor was wrong in his thinking, I would have defended him because i like him as a person. Pressuring a more entrenched follower would create an even worse result I think than had someone pressured me, and that person would more likely shut such input out all together.
Being available, passively, not actively I think is the best approach to draw off followers. But actively trying to ‘convert’ is offensive too.
An entrenched follower of a religion has I think for the most part abjecated thinking about difficult issues to their leadership, and do not engage in any true inquiry on such matters that their church has decided upon as a matter of doctrine. So arguing with them will forever be a fruitless endevor. But if, like was true in my case, the leadership of a church were to accept a more rational -fact based- approach in their culture, then the followers will too. Some may leave the church as a result, others may not. Either way the cause of rational thought is improved.