Ok, so I'll be the first to agree that Linux documentation is on the whole terrible. You can get some documentation with man, but unless you're pretty comfortable with a command line, the documentation is likely to be completely useless to the average user (I remember when I first started using Linux that figuring out how to make sense of man pages was often more challenging than just guessing how to do things). The contextual help in Ubuntu is slightly more readable, but usually useless when there's any available at all.
That said, is Windows documentation any better? I haven't really used Windows in a couple years now, but from what I recall, opening up one of the help files to figure out how to get something done was completely useless. I have generally found that I'm much more able to figure out how the program works by fiddling than by reading help pages. Less technical users (like my parents) generally can't figure out how to do things, it's true, but they also are completely incapable of finding the relevant help page - I suspect that the skills are related. I suppose what I'm trying to say is that for most end user applications documentation is pretty well irrelevant, and the real question is how intuitive the interface is. On this front I think that Windows and Linux are pretty well tied at this point, both lagging a ways behind the top to bottom uniformity you get from Mac OS.
Finally, is there really any problem with using Google as your documentation? I think that Google is the best sort available documentation on all the major OSes, and I'm not really sure I see the problem the summary is claiming exists. So, in summary, poor documentation isn't a linux problem, and I'm not even really sure it's a problem at all. This seems like a lot of fuss over nothing to me.