This is "lie to join a group" for people who don't believe, and the dishonesty has negative effects on people as well.
If it's not your thing, it's not your thing, but if 'lying' is really the only barrier, note that a lot of churches actually consider it part of their mission to work with nonbelievers and would take something like "I'm not a believer but I'd like to learn what it's like for you all" (or some other true formulation of your intentions) as a valid form of interest.
The conceit behind it is they think there's a chance you'll believe after joining.