I think the word to use here is "selfish", not "unreasonable". Basically a selfish reader would argue that the author is better omit stuff that might rub that reader wrong, and would sound that concern of his. While there is some truth to it, there's also the desire of the author to write what he actually wants to the way he wants to. Most will agree that the latter is to take precedence, but the point is, maybe it is just easier sometimes to avoid any confrontation in the first place. Again, this is for the author alone to decide.
I would also add that "with the high level of education required to enjoy LWN" one could expect a somewhat elevated level of people who are opposed to religion. Of course most of them wouldn't care, but still, references to religious content would be frowned upon to some extent.