No, I share your sentiment and I work in the accessibility space myself. Presentation should always follow the content, presentation is always secondary and it needs to be flexible.

In cases of (color)blindness, vision loss or cataract, deafness, vertigo etc. the presentation needs to adapt to the user needs while ideally presenting the same content.

With OP's stylesheet it is possible to create a visual representation that is flexible and robust, but the classlessness nature makes it impossible to support certain type of content altogether.

The elements defined in HTML have meanings. That's the semantics. If you use the elements according to the meanings defined in the standard, then your markup is semantic. Whether you use lots of classes is neither here nor there, although how you use the classes matters.