A Matter Of Inconvenience

I am starting to have a reputation in the office regarding my non-belief. I don't know why it had to be so since our company values diversity highly and put it in concrete written policy for everyone else to understand. Every opportunity, the word "diversity" is emphasized. Something that I fully believe to be sincere and effective. I believe religion has no place in our work environment so this incident came as a real surprise for me. Just the other day, A, was talking with R about something related to their project when I passed by them. I had to excuse myself since R was blocking the aisle. Then out of the blue R called on me and ask me: you don't believe in anything do you? I was a bit taken off. It was loud enough for everybody to hear and I can say I was a little bit "embarrassed" by the frankness of the question. I said, of course I believe in something. Please be more specific. In god. R: you don't believe in god do you? No, I don't. A: what? I am sure you must believe in something higher or anything like that. If you define god, I may answer in the affirmative. Now if you'll excuse me. Why did they have to do that? I never discussed my atheism with them. In fact, I don't discuss my atheism at work. Specially at work. It's a non-issue. I work in a company of diverse culture and presumably of belief. But could it be that some people simply assume that this diversity doesn't extend to non-belief in the same sense that many Filipinos simply assume that freedom of religion does not extend to freedom from religion since the constitution clearly states god almighty. Why does atheism seem inconvenient to the average believer? If I don't believe in their god, why is it a big deal? It's not that people of other religions share their belief so why is atheism being singled out?