Take a step back and ask yourself question: does it matter? I can see where you're coming from; but, honestly: is your life going to be at all impacted by the name of an individual color?
On a case-by-case basis: that's probably fine. (A) It is unlikely to come up too often (lots of people don't have a favorite color), (B) while every named color adds a bit of burden to standards compliance, the bit is so terribly trivial that it's not worth mentioning; it's a single additional line in a lookup table.
There's no precedent issue here to concern ourselves with.
It's the twenty-first century. Assuming we open a precedent that some day grows the named colors to 40,000 entries (which seems like a stretch)... Is maintaining approximately 1.4MB of data in a lookup table really something we are afraid we can't do? I'm pretty sure my computer has forgotten how to count that low.
Is it even a significant burden on the creation of new standards-compliant web browsers? Explain to me how we could go about crafting the development process of a new web browser where populating its table of named colors doesn't reduce to throwing a couple of scripts at a standard normative document to convert that document into the language-du-jour.
Fear of precedent on this question is practically over-stated.
