I think this article is too dismissive of well-conceived responsive development, especially with recent advancements in CSS.
For instance: “HTML markup decides the order in which the web page is rendered.” Well, not with flexbox.
“On a desktop, you want the menu at the top, easily visible and accessible, so that the user can navigate easily. On a mobile device, being able to see and access real content first beats being able to navigate to other pages. So you don’t want to load your menu first. It’d be better to have a collapsed or simplified menu at the bottom of the screen.” Um, which is pretty much what the overwhelming majority of responsive sites in fact do.
“Take media. Even if you use CSS or JavaScript to resize images, usually you end up loading the larger image first and then scaling it down.” Only if you don’t know what you’re doing.
I can understand and accept the arguments from user experience: there are cases where you may genuinely have a different target for a mobile site. But instead of throwing out arguments based on poor implementation (which can be overcome by a good front end developer), I suggest it would be more helpful to focus on the real issues.