Yes but you can't really expect to walk into a church without being ready to give an account of your beliefs. If you have no reason to be there, why are you there? Of course everything can be OTT. So I'm not excusing what I don't know but if you walk into a church, people have a right to question you.
So put a sign on the front door saying 'Nobody Allowed Who Disagrees With Us'. if people question me, then I will state what I think, especially if they question repeatedly. if I am attending a wedding or a funeral (which non-believers may well want to attend), then it is simply rude to ridicule my lack of belief if I am being otherwise respectful.
As I have pointed out, churches are not public, unless State churches. P.u.s.s.y. Riot were jailed in Russia for descrating a State church. There have been many thefts from churches. If someone has no purpose being in a church, may be their intentions are malicious.
Is going to a wedding or funeral such a purpose? How about if I am invited by a member?
Heck, the espiscopal church in my current locale (an 19th century building) currently lies in ruins, having been burnt down by some atheist jerk, whom was later jailed, incurring a $multi-million loss to some insurance company.
There is a LONG stretch from stating a differing belief when asked and burning down a building, don't you think? Maybe you should cool off a bit and realize non-believers often have legitimate reasons for being in a church (how about non-religious group meetings, which often happen in spaces rented from churches?).