However, they needn't be stupid. Ignorance is sufficient. Alas, one of the problems with ignorance is how little it is recognised. Hence my concern with the design of tools in general. Hence my distinction between tools created by programmers for programmers, and tools created by programmers for non-programmers .
Nobody has to pass a test before becoming a web designer.
Thus, few of us know what we need to know in order to do web design. Few people even know low little they know. No tool can know enough, but at least tools can be designed to do as little harm as possible. I doubt it.