I love CSS's pseudo-selectors. In my opinion, they are the best part of CSS3 and are generally great.

However, I think the author's jabs at CSS pre-processors and their adherents are unsubstantiated and a little unfair. I don't see how using SASS precludes you from knowing about or using complex selectors. As the author points out, SASS is merely an efficient and more intuitive way to write classic CSS. The good parts of CSS are still the good parts of SASS, and by definition every feature of CSS is a feature of SASS. It doesn't really follow that using SASS predisposes you to be less knowledgeable about regular CSS.

If anything, people using SASS likely use many more complex styles and work on larger projects, and are probably know more about and actively use more aspects of CSS than do people who don't have a need for SASS.