It is true though, MHMMaM. I have experienced the same. Let me say that I am a believer but before I was I met and mixed with some quite extreme Christians who were very nice but would convey all the sentiments that you have listed, were often quite insensitive and tactless, single minded and somewhat complacent. There was also something of a glassy stare. I was a grown up but sometimes felt confused. I was much happier later, in a more mainstream setting which was more human and - for want of a better word - "normal".
I have also come across those attitudes on forums, I tend to ignore most of it or talk about something else of a lighthearted nature, but I've heard of people being accused of arrogance and defiance because they don't believe: they don't believe because they can't believe, it isn't a question of deliberately not believing. It can be off putting, certainly scary for younger people and those of a sensitive nature. Not everyone has a gift for evangelism, some definitely should keep schtum.
(Btw, I noted your nickname and feel very sorry that the mods have removed your vocal cords. They should be prosecuted. )