Coffee is to be served hot.
No, not nearly that hot. Most drip coffee machines *brew* it at the McDonald's temperature, but it is kept at a much lower temperature (around 160F) in the carafe. One reason for this is that it rapidly loses quality if you keep it too hot.
People know what temperature coffee is almost universally served at, and they take the appropriate care. If you fill a cup of coffee from a coffee machine to the brim and carry it around, you just don't need to be that careful because it's just not that hot (unless it's from McDonald's). If you fill the same cup to the brim with water at a full rolling boil out of a pot, you're damned well going to be instinctively much more careful with it, because a small splash could give you serious burns.
You may now post one of your typical obscenity-laced abusive replies. It won't make you any less wrong.