When you say transcendence do you mean universal applicability?
Transcendence by definition implies universality. Applied to mankind it means the
transcending of our many cultures into an ever smaller number of ever larger ones, mixing both the motifs and the people.
If both Americans and Islamic militants are resisting transcendence, what exactly is supporting it?
This is a perfect illustration of civilization as an organism unto itself, which
transcends the individual people and the individual cultures that create and sustain it. Civilization has proven to be an incredibly robust creation that has survived countless threats and endured long periods without being nurtured.
Of the six independent "civilizations" whose discrete creation we know of, three (Egypt, Aztec and Inca) were actually destroyed by one of the others (Mesopotamian, at least its Arab and Greco-Roman offshoots). These determined assaults continued, as Mongol barbarians tried to take down the former and Germanic barbarians made an earlier attempt to "Vandal-ize" the latter, and they all ended up not just assimilated but becoming important contributors: The Mongols became the Ottomans and took over the Arab empire; and the Germans need no introduction, except to point out their own ill-conceived attempt to conquer Greco-Roman civilization which resulted in the destruction of much of it, which was quickly rebuilt stronger than ever.
A whimsical economic system starved much of civilization for the surplus wealth that feeds its growth for decades, and the discovery of nuclear energy held it hostage for almost as long, yet still it runs along with barely a hiccup.
It's obvious that civilization
transcends us. The greatest phenomenon of our period of residence on this planet is the creation of something that we have not just proven unable to destroy, but that we can't even slow down.
The answer to your question is that civilization itself supports transcendence. We seem to have built it that way so that's the way it works.
There's a ratchet effect at work here. Our unconscious efforts to promote transcendence are more effective than our conscious attempts to restrain it. Some Americans (and for the record it's just a loud minority of us) may think that they're holding off the assimilation of our melting-pot nation (what irony) into the Global Civilization, yet it's we who provided that civilization with some of its most incredibly powerful tools of transcendence, such as the internet, and before that rock and roll, which united the youth of many nations. The irony is just as rich in Islam: the largest Muslim country is Indonesia, where the influence of the Greco-Roman, Chinese and Indian civilizations is rampant.