I hope you don't mind me being technical here, but you can't
copyright the words "Krispy" or "Kreme" either. For example, if someone wrote a novel where the main character was called "Krispy", and that word appeared 100 times in the story, the Krispy Kreme company would not be able to complain that their copyright had been infringed.
You're right, though, that "Krispy Kreme" can be a trademark, and someone probably couldn't register "Cream" as a trademark for a brand of cream. However, "Crispy Cream" is probably specific enough that it could have been trademarked (assuming "Krispy Kreme" wasn't already trademarked). Also bear in mind that it is possible for a computer company to be called "Apple", and that's a fairly common word that is found in dictionaries.