Is there anything out there that doesn't offend people?

Last night, I upset a Black guy from Atlanta in one of my cles. My professor is Australian. I mentioned to a female clmate that I wanted to see the Southern Cross one day. The Black man, who was eavesdropping, got so offended and pulled out the race card. I guess he implied that I was referring to burning crosses and the Ku Klux Klan. That's not even in the same ballpark as what I discussed. I was talking about the constellation in the sky that forms the Southern Cross. You can only see that in the Southern Hemisphere just as you can only see the North Star in the Northern Hemisphere. It made no difference when I explained to him that my last roommate was also Black, and I have recently started dating a Hispanic girl whereby ruling out any possibility of me being racist. This past summer, some girl on here from New Zealand got so when I asked if she was from Auckland. I then articulated that when I meet someone from abroad I ask if they're from the primate city. What I meant was the largest city in the country disproportionally larger than the rest. It's the entire cultural, economic, and political hearth of the country. Primate cities have vast amounts of small townships in their surrounding peripheries. This girl thought I was talking about a city full of monkeys and apes. She never bothered to look it up on Wikipedia. Later, I explained why New York is not a primate city. The reason is because it's neither twice the size of Los Angeles, nor does it outshine L.A. in every category. L.A. is also a global city, and most of our imports come through there now and not New York. Not every country has a primate city. Mumbai is not a primate city because of Calcutta and Delhi. A few New Yorkers got so mad because they thought I was dissing their town, when I was only giving a plausible explanation. I know the truth hurts some people, but so be it. In the meantime, is there anything out there that doesn't offend people? How can I be politically correct if they keep changing all the rules?