Design is not art.
No, I don’t mean that design isn’t artistic. I mean that when you ask the questions “what is art?” and “what is design?”, you get fundamentally different answers.
Art has no function, it’s pure form.
Design has form and function, where the first priority is function.
So, to complain that accessibility is a creative barrier to good design, is like complaining that nutrition and hygiene are barriers to good cooking.