And, to address the question (and the grand ghost of Chuck Dixon), the description of the suit as a "Nomex Kevlar bi-weave" seems misinformed as to how Kevlar or Nomex work, and is unreasonable based on the actual look of the suit in question.
You know what Denny O'Neil said Batman was wearing when he beat Jean Paul "I'm a better Batman than you look at my massive armor" Valley and took back his mantle from a weepy brainwash case? Silk. In Winter. Because he's the goddammed Batman.
In real life, the two are not that flexible when it comes to something like what is worn in the comics. Hence in the Batman films, especially the Nolan ones, the suit is rather bulky and restrictive. In the DCU, Batman's cape is made of that, but the formula is altered so that it allows for movement, while still allowing for protection. It's psuedo science, but that's pretty much the explaination.