So I think your view of a prevalence of Christian declarations to be, at least in part, due to how likely holders of certain beliefs are to consider their proclamation of such as being acceptable (to themselves and to others perceived as likely to visit PerlMonks).
I agree wholeheartedly. It is very typical of US Christians to advertise their faith. They take that evangelical thing quite seriously. People from other faiths and other countries tend to avoid this---indeed, in many cultures, it is considered bad form because of the tendency of religious discussions to get out of hand. In other countries (e.g. Italy, Yemen), the likely answer is so obvious that there is no need to discuss it.