But you offer an Apples and Oranges comparison. Giving the finger to a lady and her kids is definitely being an arse, perhaps worth of acquiring a lump for his rudeness. Not at all the same as being offended by the use of a perfectly good descriptive word just because of current PC guide lines.
All i'm suggesting is that when you have other options, use them instead of purposefully offending. No one is saying you can't, it's up to you. But just as you judge people based on the language they use, people judge you based on the language you use. synonyms for Nig#ardly include stingy, skimpy and one of my favorites, miserly. Those are just a few off the top of my head, I'm sure you can come up with a bunch more. I would defend your right to use those words, I would simply ask that you consider not using the term, especially if it's around people who may be unaware of it's etymology.
Using that term is trying to beat the system on a technicality. When you hear of a lawyer beating the system on a technicality? What do you think when a politician gets out of a promise based on a technicality? You can do it, but it makes you look like a vengeful, vindictive creep.