While a diverse education may cultivate your mind for better performance, not everyone agrees that it's something you must learn and even be assessed on. I would say that's better for highschool level learning (general skills and preparing individuals for society). In university, you're paying to study for your field. More often than not, it's to receive qualifications to work.
Looking at it through this qualification lense, you're basically saying that I (the professor) can degrade your overall mark due to a compulsory, non-related subject.. thereby making you seem less qualified based on overall academic merit.
A "better" person compared to an "average" person is evaluated by other people through an interview, not by a High Distinction in visual arts.