Whenever Christians engage in an exchange on the Internet about anything of almost any substance whatsoever—gays, hell, universal salvation, infallibility of Scripture, women as clergy, cushions on pews, colognes worn by pastors, cookies vs. donuts, off-key hymn belters—it’s inevitable that some Christians will start declaring that other Christians in the conversation aren’t really Christian at all.
I can’t imagine being at an Elk’s Lodge meeting, and having one of the members stand up and say something about the minutes of the last meeting, or whatever—and then having another guy stand up, point at the first guy, and bellow, “You’re not a real Elk! You’re not Elkian!”
If you’re a Christian who has ever declared that someone who says they’re a Christian isn’t, please stop doing that. It makes all us Christians seem just a little more stupid. You have no idea who is and isn’t a Christian, okay? Worry about your own soul. Let God worry about everyone else’s.