WASHINGTON—Whenever I write sympathetically about religion, I get bombarded by tweets and notes from readers who normally agree with me but cannot abide the idea that religious belief should be seen as intellectually serious. And because I have written favorably about Pope Francis, I get more than my share of angry comments about the Catholic pedophilia scandal, which continues to haunt the church and troubles even its most loyal members. Getting lambasted doesn’t bother me. On the contrary, citizens talking back to the purveyors of opinion is a glorious aspect of free speech. But my correspondents underscore the existence of...