Reading this article from The New York Times Magazine the other day about American born jihadist Omar Hammami, this passage (among many, I might add) about the Salafi Islam movement that Hammami embraced caught my attention, "Followers of the movement, who are sometimes likened to Calvinist Protestants, advocate a strict return to the fundamentals of Islam. To purge their practice of modern influences, they try to emulate the founders of the faith — the contemporaries of the Prophet Muhammad and the two generations that came after his death in A.D. 632. Young Salafis, for example, often dress in sandals and robes like those thought to have been worn in seventh-century Arabia." (Underlining mine).
Around the same time, I had read this article in the February 2010 edition of National Geographic about Mormon polygamists in the United States. In this picture, the caption notes that "[f]emale FLDS members wear modest attire—ankle-length prairie dresses—even while swimming." The Mormon Church was established in the mid-19th century United States, and early adherents of the faith had trekked across the United States to Utah. The women in the FLDS wear basically the same kind of clothing as what women wore in the United States some 160 or so years ago.
I found myself struck by the obvious but previously little thought of fact that for many fundamentalist religious believers, what clothing they are required or aspire to wear is essentially determined by the clothing specific to the time and geographic location of that particular religion's founding.
I started to think of other examples of this. Another obvious one to me are the Amish, who trace their origins to late 17th century Switzerland. You also see this with Hasidic Jews, whose sect dates back to 18th century Poland. From this Wikipedia article, "Much of Hasidic dress was historically the clothing of all Eastern-European Jews (and non-Jews), but Hasidim have preserved more of these styles to the present day."
The difference between Hasidic Jews and the Amish, as compared to Islamic fundamentalists, is that the former two are generally insular groups, whereas Islam presents itself as a universal religion that seeks to convert everybody, regardless of their race, nationality, or culture. Thus, pious Muslims, wherever they live, assume the clothing habits of a 7th century Arab desert culture. It's one thing if you happen to live in a desert environment, as many Arab and North African Muslims do. It's another thing when you live in tropical South East Asian countries like Indonesia and Malaysia, where Islamic dress strikes me as rather incongruent.
While the sentiment might exist in other religious cultures, one feature I have noticed with Islamic fundamentalists is that their vision of an ideal society is frozen in an idealized past where the Muslims were supposedly better Muslims than the ones who came afterwards. Thus, they feel the need to dress like they think the prophet Muhammed would have dressed, and to eat what they think he would have eaten, and so forth. Or, to borrow from a popular Christian song, "It was good for Muhammed, and it's good enough for me." But, as I believe I have demonstrated above, one's ideal of religiously appropriate attire is arbitrarily dictated by the time, place and culture of that particular religion's founding.