Curlew, no one on this thread is arguing that faith trumps all arguments. The pros and cons of, and people's reason to opt for, circumcision in a variety of societies, have been explained over and over. You are evidently not receptive to them.
I have to disagree with this. People who circumcise NOT for reasons of faith may well will have given serious thought to 'the pros and cons and reasons to opt for', as you say. Over time I think the practice is, and will become common less and less common when Islam/Judaism has no cultural or religious part to play in the decision.
On the other hand, people of faith (or sometimes just people who are Jew/Muslim by cultural identity rather than by any actual genuine faith) will probably never stop to consider the pros and cons and reasons to opt for. It is so culturally ingrained in them to just do it anyway that they suspect someone already found the answer out on their behalf, a few millenia ago (because obviously there were so many very accurate peer reviewed medical studies back then. 
)
Even when something forces them to consider an alternative view, and even if they could be shown unequivocally that there is:
no blanket need
no blanket justification
no net benefit (for all circumcised men as a whole)
some serious risk both in the long and short term
sometimes even death, through botched procedure
not to mention the very contentious issue of what many see as cruel physical assault
they are, in overwhelming numbers, going to feel a sense of cognitive dissonance that is so all consuming that there really is nothing anyone could say, or show them to change their minds.
That is where faith trumps all argument.