It matters if userspace and the kernel are developed by separate teams, as is the case with Linux. If you break the kernel interface but have a library with a stable interface then you can't support static linking (which fell out of favor for a decade but is now back in style).
Right, and the article seems to have some sort of axe to grind with Linux, so the author paints "developed by separate teams" as somehow an inferior choice deserving of scorn.
I generally found the article to be light on technical accuracy and heavy on pointless "my OS is better than yours" prattle.
