I never post on this board, so forgive me for butting in. I just wanted to let you all know that I found an awesome siggy banner at https://r-word.org/
<a href="https://www.r-word.org/"><img src="https://r-word.org/SO_180x150.gif" border="0" alt="r-word.org" /></a>
I'm proud to have it on my signature, and show my support!
A few weeks ago, my boss used the phrase "Charles-tards" to refer to our coworkers in the Charles building of our complex. I was shocked - and rather than hide my reaction, I said, "oh, my, I can't believe you just used that word." He didn't realize it was an offensive term.
Since it's after the fact for you, Taffy, I'm not sure how you could revisit the matter. In the future, though, try a gently surprised/shocked reaction - it works in many situations.