So can the information on how you should partition your hard drive for Linux installation. Yet (historically) most people think Linux installation is a usability disaster.
Or for another way of looking at it, do you really think that an interface which requires you to go online (or read a manual) to figure out how basic stuff like undo or delete work represents "good usability"?
Also, as the author points out, what is "refresh" supposed to do in the context of a single message? Just because a symbol is familiar, it doesn't mean its meaning is automatically clear if it's taken out of context. For example, at my workplace recently got a new microwave that has a play/pause button. In this case, it's relatively easy to figure it out but it still gave me a pause.
You do realize that this is the developer's classic response to a usability issue? The user is just clumsy/stupid/lazy/ignorant/blind/stubborn [pick one]. I'd agree that you can't make UI decisions based on one person's reported problem, but the correct response is not "RTFM" but "This issue should be tested in a usability lab with a reasonable cross section of the target market".
That's the thing. It was. And it works for everyone I've ever met, including my wife and my parents who are the polar opposite of 'technical'. I'm not making baseless claims of the user being [insert one of the choices], it was based on my (rather extensive) experience with the device and users of it.
Also, the other glaring example here is the one about the mail client refresh-vs-reply arrows. Aren't these two icons the exact same icons used for pretty much the whole history of the internet? Circular arrows = refresh; Left arrow = reply.
New things sometimes require just a bit of effort because you aren't familiar with it. In other words, easy-to-use != just like every other phone out there. It's pretty close to a 'fundamentally new UI' - just because you don't grok it within 5 seconds doesn't make it hard to use.