It's somewhat akin to giving someone a kitchen full of appliances, foodstuffs, etc. and then they refer to themselves as
chefs.
With 32 years of teaching visual arts to younsters I certainly agree that a basic understanding of the elements and principles of design are necessary. You do encounter the rare person who may have a gift of knowing what "looks good" but I can count on my hands and toes the number of students I've had who qualified for that category (and I've taught thousands).
It is very heartening to see some of my former pupils now working for Marvel Comics, animating for the X-men movies, and illustrating for leading publications. All those individuals were noticeable for their grasp of the objectives and skills that were being taught with each lesson and I still remember them after all these years. But I think the most gratifying are the students who learned to think in more abstract and diverse modes yet were able to pull the ideas together to do something useful. These are the kids who were able to adapt to changes in their lives and evolve. Let's hope that some of those wanna-be web designers are from the latter group.
Unfortunately a visit around the net these days shows that there are far too many cooks in the kitchen who think they are chefs.