I thought he was joking — at first. But no. Bill O’Reilly really does not know that the moon’s gravity causes the oceans’ tide.
Since he asked, I can think of reasons why a non-believer would still attend a religious service he or she does not hold is true. There are financial and cultural pressures to keep up the facade of belief. It may also be the familiarity and belonging that worship service provides.
The “tone” argument used against atheists is a little tired and counter-factual. But it plays into a victimhood mentality that some people (including atheists) like to cling to. It is diversion from the real issue, which is not the style of argument, but that there is an argument at all.