Blog posts like this remind me how badly CSS needs to catch up to where preprocessors like Less and SCSS are at.
I read things like this:
Just because your menus and your buttons share the same border radius
and font size doesn’t mean those styles should be
abstracted away into some third class that gets
applied to both elements.
From their other writings i assume the author uses pre-processors but they also practice a form of object-oriented CSS, which is concerned with the final compiled CSS.
Mixins are great but they can still compile to overly repetitious CSS. Even with mixins, you still have to think about and decide on the structure and how much repetition should be in your CSS.
I read things like this:
and want to shout out: "Just use a mixin!"