Religious people read religious blogs. Atheists read atheist blogs. Why?

I've been reading a blog written by a devout Catholic.  She writes well and provides much fascinating food for thought.  But those submitting comments are almost exclusively her fans, telling her how wonderful she is.  Am I so unusual in wanting to get involved in blogs by people with whom I do not agree? --  not as a heckler or someone who writes very rude childish comments, but as someone who is genuinely interested in understanding a very different point of view, and politely putting forward an alternative one.
It's a little worrying that so many bloggers swim in their own cosy circle of admirers, who hang on their every word.  Surely it is only by being challenged that we are forced to confront our doubts, and we come out of the exchange either confirmed in our beliefs or able to modify them in the light of new information or arguments.