It has nothing to do with claiming innocence for atheists. I've never heard any christian say they were "chatted up" by an atheist wantng to tell them about atheism or "convert" them. IF they ask I'm sure there are plenty of atheists willing to tell them. And IF either atheist or christian go to forums such as this one, or ones specifically for atheist or christian, then they are giving permission in a way, to be preached at or hear about atheism or religion and they can decide on their own how much they want to hear or read about it. For instance, I don't read bill's or gb's sermons, If I've ask a question I might read the first paragraph to see if they addressed the question, but if they don't, and launch into a bible lesson to avoid answering, which they do most of the time, I just move on. And they're free to do the same.