There is a lot of pretending going on.
First, I will note that I use a lot of color in my CAD designs. But because I am aware of the common disabilities with color vision, I am careful to choose colors that are more easily distinguished. I also try to choose colors that will print in b/w with different shades of grey, and often also use line types (different kinds of dashes). Those may help some, but someone who is color blind will likely not be able to discern all the things in my drawings. But, I won’t reduce the use of color that will reduce the ability of most people to understand the drawings.
I disagree with some of the things in this course. For a minor, but clear example, we are tasked with creating content that strengthens the learning process. But, then things like "don't use color" are stated, even though the use of color has long been considered a good tool to enhance learning. So, the result is to reduce learning in the general population, to accommodate some, but pretend that it doesn’t.
It is somewhat like back when some K-12 schools started dumbing-down their education for the purpose of increasing graduation rates in the name of equity. Yes, more kids got diplomas. But those who could have benefited from the higher levels of education were made to suffer.
