Good point, but of course installing a decent browser is the counter argument. Admittedly my 3 year old Nokia may not be very representative, but its Opera Mini version solves that problem beautifully. My hunch is that it uses heuristics to find the main text area (which nearly every site has), and adjusts the css of that block to $SCREEN_WIDTH. It's been able to do this ever since I started using it in 2009. Now, I've lived under a rock since then, but are you really saying that your mobile browser doesn't do something like that?
I believe it's such browsers that the author was referring to.
Still, admittedly, using heuristics to patch the css shouldn't really be a browser's task, so your point holds.
If you are building a modern day site, there is just no reason not to make it mobile (phone/tablet) friendly. If you don't want to redesign an existing website, you can just make a separate site that redirects, but which is a less elegant solution.
I believe it's such browsers that the author was referring to.
Still, admittedly, using heuristics to patch the css shouldn't really be a browser's task, so your point holds.