Eloethan's examples are all of things which have connotations of going on in darkness, hidden from the light of open scrutiny, or of gloomy moodiness - literally so and have been for centuries, nothing whatsoever to do with applying them to skin colour, and anyone who takes it to themselves as an insult is working pretty hard at being a martyr, whatever their previous experience of discrimination.
In fact, most people who are not "white" are not actually "black" at all, but some subtle shade mixed from reds, yellows, browns, pinks, and even other colours.
Is it also insulting some race or other to use yellow as an adjective for a coward, pink for the noise of a faulty car engine, brown sauce for a condiment made chiefly of tooth-shrivelling vinegar and eye-watering spices, reds under the bed for fifth-columnist sleepers, white nights for hours of agonising sleeplessness, beige for boring?
How about the patriotic ladies who gave white feathers to "cowardly" men who were not in uniform? Was it an insult to the "white" forces who WERE in uniform?