That's obviously nonsense, however, there are also plenty of legitimate Japanese sword arts that use the edge parry. For instance, Yagyu Nobuharu, headmaster of the Yagyu Shinkage Ryu (the style of the Tokugawa shoguns) recently announced that parries in the Yagyu Ryu are indeed to be performed with the edge, and said that trying to avoid the edge parry was "such an Americanization."
That doesn't make it a legitimate or historical technique. A lot of sport fencers will tell you things about WMA that are completely untrue, and oft-times suicidal. Unless Yagyu Nobuharu is a shogun, and fought in those battles, he's a modern practitioner advocating a flawed technique.
In the real world, you simply can't bang two sharp pieces of steel together without damaging one or both. This is both basic science and common sense.

