I hate to say it, but that article is inaccurately reported, and I cringe every time I see it linked. It conflates the PAL codes with the presidential launch codes, which are two distinct layers of security. Even if the PAL is hard coded to all zeros, you still need presidential authorization to initiate the launch procedure.
Well, as long as it wasn't stick by the silo entrance on the wall on postit we can call it an improvement, eh? I mean you have to at least remember the number of zeros required