Are there ANY derogatory names you would find offensive to be called? If you’re so thick-skinned that you really don’t care, then okay, though you’re almost certainly in the minority.
Yes, I would fine most
personal insults offensive, I'm not that thick-skinned. But you would probably agree that personal insults are very different from ethnic nicknames?
I have to believe most people feel offended about SOME word that refers to their ethnicity, race, nationality, religion, maybe a physical characteristic, or whatever.
Those are all different, so I will take a liberty of picking "ethnicity, race, nationality", and putting "religion, and a physical characteristic" aside. Why would anyone be seriously offended by a nickname referring to their ethnicity, race, or nationality, especially if used by a stranger in a non-threatening scenario?
When such term is used, it means a few things: 1) an opponent makes an assumption about me representing certain group, which may or may not be correct; 2) an opponent displays their attitude toward that group by using a jargon term (which may be the only term they know, by the way). Assuming the worst case scenario - meaning they assumed correct, and they do have certain negative attitude towards the group I represent - why would I be offended?
Do I believe that any of the groups I represent are universally loved? Absolutely not, and I'm fully aware of that. So if I'm facing someone who doesn't like my group, and I'm not in a situation when I depend on them or they can threaten me, why would I care one way or another how they feel about my group? If anything, I'd be glad they showed their true colors, rather than hiding behind fake facade of political correctness.