That's not what the article says. The articles says it looks and feels like a poly when you get it out of the package. But, you will notice that the stiffness is significantly below Prince Synthetic Gut which is a nylon string that is below the normal poly stiffness range. You'll also notice that several of the playtesters praised the string for improved comfort, even if they didn't follow Ashaway's guidelines concerning reducing tension. The article also noted that it does not act like a poly during stringing.
Zyex is a string material that plays softer at lower tensions and stiffens at higher tensions. It is more gut-like than other synthetics at lower tensions. In order to get maximum comfort out of it, you need to drop the tension down 10-20% from what you normally use like Ashaway suggests. If you want a synthetic string that doesn't stiffen as much at higher tension you may want to try a polyolefin ribbon type string, like Isospeed Control Classic. Natural gut also, based on TW's data, resists stiffening as tension increases much better than synthetics — making it the best choice for players prone to pain from ball impact shock who want higher tensions.
As for Zyex Monogut being stiffer than Dynamite, that's hardly surprising since it's a monofilament string. Monofilament strings are always stiffer because they are a single filament. Old Dynamite has something like 6 Zyex filaments that are wrapped. New Dynamite has a large number of fine filaments, as far as I know. Testing data finds that old Dynamite isn't stiffer than new Dynamite, with the exception of the 18 gauge Soft which is thinner and less stiff. Interestingly, the 16 gauge of the old Dynamite tested slightly less stiff than the 17, at least at some tensions. I have found the 16 more durable and resistant to movement. I prefer it, although the 17 is a nice string for a racquet with a dense pattern.