I think some of the shown examples exhibit dark patterns in CSS authorship. For instance, unneccessary nesting happens when you use a CSS preprocessor such as LESS or SASS and basically structure/nest your CSS following the structure of your HTML (instead of writing a CSS file orthogonal to the HTML structure). That will generate bad and bloated CSS code which is slow. This habit exists since >10yrs (as LESS/SASS date back for around ~>10yrs).