Yeah, that was confusing to me, too. I saw the article's first example and thought, "Well, that's not really responsive design, that's switching between two entirely different views!"
On my personal site I do indeed have a media query to make some tweaks when the viewport is phone-in-portrait-orientation narrow, but I try to keep them pretty minimal. I find sites that reorganize themselves at different widths ("if your browser window is 2000px across, this is a three-column display instead of two!") to be…not necessarily bad, but at best, unnecessarily clever.
On my personal site I do indeed have a media query to make some tweaks when the viewport is phone-in-portrait-orientation narrow, but I try to keep them pretty minimal. I find sites that reorganize themselves at different widths ("if your browser window is 2000px across, this is a three-column display instead of two!") to be…not necessarily bad, but at best, unnecessarily clever.