The problem is, in my opinion, is that what constitutes offensive verbal behavior has changed over the decades, and seems to be getting to the point where a dictionary of offensive terms may have to be published, and even taught country-wide, if all people are not to be offended.
An example, in the South it can still be considered acceptable to ask someone, "Are you Jew?" (Just like asking someone if they are Protestant or Catholic). However, many people wanting to not be offensive would ask, "Are you a Jew?" And, the evolving sensitivity of many Jews (at least in nyc) would appreciate the question be phrased as, "Are you Jewish?" (since "Jew" has be an epithet in itself historically).
I once heard/read that only WASPs do not get offended when a joke uses them as the butt of the joke. That could be because their self-esteem is on the top of the self-esteem food chain, so to speak. The rest of us are hypersensitive. But, if one knows of offensive verbal language being directed to one's own group, then hearing a hypersensitive reaction could afford someone a moment of gratuitous schadenfreude. Naturally, there is a tipping point where "black humor" goes beyond the pale for some, especially when the perpetrator is outside the "in" group of recipients of the offensive behavior. For example, I have heard Jews (aka, Jewish people) tell the joke of two Jews waiting in line to go into the gas chamber in Nazi Germany. Being a lovely spring day in Poland, one Jew started to whistle a song from his childhoood. The other Jew said, "Shhhhh! The guards don't like whistling."
My point is what is offensive can be based on who is saying the offensive verbiage. If it is one who "should" not broach the verbiage, it is offensive, but someone from the same background can be considered, perhaps, to just be making a poor attempt at humor. We have differing kindling points for being offended. And, as an aside, once upon a time, when we valued stoicism, many person was proud of the inability to be offended. That also is, in my opinion, a requirement to remain in a job, beyond the honeymoon period afforded a new employee (could be a test by management to see if one is worth keeping as a long term employee?).
I'm sure you understand the depth of insight in this posting.