Woah, oomis, just a second,
Noone EVER said it’s a halacha (at least noone I know of). It’s an issue of sakana & simply depends on how catious one’s Rav feels he needs to be. Generally these sort of things go by community minhag.
I’ve never heard of staying out of the shul or chapel & being that the whole issue is avoiding “mazikim” that frequent cemeteries it would seem that the shul or chapel would’nt be a problem.