But most scientists work as part of a wider community of scientists.  They may, in fact, interact primarily or exclusively with other members of that sub-community.  Like any community, there are rules and norms and values and whatnot that govern the way in which people commonly behave in that community, what is acceptable and what is not, what is usually done and what is avoided, etc.

Some of these norms and values come from the nature of their collective endeavor, and some do not.  An emphasis on accuracy, reporting one's findings, and discussion thereof are community norms, but norms that stem directly from the practice of science - if they weren't doing these things, it wouldn't be science as we understand it.

Other things, like the violently negative attitude towards such things as astrology, are not.  There is no reason inherent to the practice of science that says obvious non-rational fallacies like astrology must be attacked with arrogant contempt - complete disinterest, or magnanimous bemusement seem equally possible, even though they are currently minority responses.

To put it another way, not every scientist has to come across like Dawkins, but the fact that a good number of them do (including many friends of mine in different fields) indicates that a particular group culture is at work.