There may be no consensus, but there is a correct answer. People in different regions could call coffee with tree bark in it “Black,” but that would be a bastardization of the term; so it is a bastardization to call coffee with only sugar “Black” even though it is in fact that color.
When we talk about coffee in terms of its color “Black,” we are referring to more than just its color, and this is the beauty of language. Language allows us to say what we mean in a clear manner, even if the ignorant masses (not stupid, just ignorant) cloud the facts with a team of like-minded wrong-way thinking.
When someone asks how you want your coffee and you say, “Black,” you are in fact asking for coffee with nothing else in it, but that’s too easy. Let me make a case.
If you say “A little sugar” it is clear you want a little sugar, though the exact amount is up for interpretation. You will most likely add your own sugar anyway. This sounds like you are a formal guest at someone’s house and they are going to serve you coffee. Regardless, “A little sugar,” or “A teaspoon of sugar” is quite clear.
If you say, “One cream,” you have made your request clearly and successfully. You will likely get your coffee as desired, though you still won’t know how clean the cup really was when pulled from the cupboard.
If you say “Cream and sugar,” in any of its myriad of variations, you’ll likely get both ingredients in your coffee, and you can then enjoy some nice conversation.
If you say, “Black,” You have left out all ingredients in your request. You simply want your coffee straight so you can enjoy the taste of the coffee, something impossible to do when adulterated.
When people now claim that “Black with sugar” is still legitimately “Black” coffee, I would say that they are correct in terms of color, but we see wasted speech, a bit of irrelevance. The color of the coffee in this case has no bearing on how you want your drink. We could say that we want our coffee wet, but that would be ridiculous. The fact that the coffee is black is just as ridiculous a point to make. The person putting a single sugar cube in your coffee can plainly see that there are no colors in the coffee. It is obviously black, wet, and (hopefully) hot.
Such pointless commentary is why people coined the term, “Captain Obvious.”
I can wink at someone and let them know I think they are cute. I can wink at someone and let them know I am just kidding. By the same token, we can say that coffee is “Black” and be referring to more than just the color of the coffee. We can also be referring to a lack of ingredients.
Forgetting about sitting down to order–thinking only in terms of the question for the debate, it isn’t fair that the ignorant force those in the know to specify what they mean by black. If you want to say the word “black” when you order coffee with sugar, for some strange reason, then go ahead, but don’t make me specify “Black, no sugar.” I choose to say what I mean without the superfluous. The next thing you know, I’ll have to say, “Black, no sugar, no flavoring, no anything else Starbucks might add that doesn’t have a color” just because there are/may be a multitude of ingredients that trend, but don’t add color to my coffee.
If “Black” coffee is not sufficient to indicate “No ingredients,” then it really doesn’t mean anything at all. Think about it. If “Black” could mean “Nothing but coffee” and it could mean, “Black with sugar,” then you would have to clarify what you mean by “Black” which would mean that “Black” is not clear by itself; therefore if “Black” is intended to be clear and complete, it must have a single meaning. Since “Black” does not state “sugar” outright, and since “sugar” only requires the word “sugar” to be requested," then “Black” must mean “nothing added”…and it does!
Why the attitude? Probably because you were bullied as a child.