I think it's possible only if the questions have nothing to do with religion, sex, politics, or is a subject that generally has no conflicting interests. "How was your day?" is usually a safe question, and possibly the only one.
Beyond that, there will always be someone who is offended by the most innocent of questions/comments. These are the people who harbor a deep resentment or bitterness towards someone or something, and they will lash out in whatever way they can.
Yahoo! forums are a safe place for such people, because they can vent their hostilities from the privacy of their own homes, without any sort of repercussion.
So yes, there will always be someone who is offended, and it will usually be these people. I suspect most Christians, Atheists, Wiccans, etc. are comfortable enough with their beliefs to be tolerant and respectfult of another's religion.