Just respond in kind, russians hate to be called communist or bitches (communist is self explanatory and bitches well almost 90% of their women are), greeks hate to be called romans, turks or nazis (just three sides that kicked their ass in a war, although they lost every war they were) or poor (they are the poorest country in Europa and part of Asia/Africa), south americans hate to be called spanish and spanish hate to be called south americans (again self explanatory), chinese and koreans hate to be called dog/bat-eaters or japanese (for some reason they think they are different), people of united states hate that someone call their country united states (they want to be called america, they dont know the difference between a country and a continent), and many more.
But not only this, for example check this post
you can say anything about cancer to ordinator and all RS gets "offended", and im sure you can find more of these cases in other clans.
Of course you can keep reporting them, in fact antifun, nansey, beastinside and a few others all went weeks crying in hero and discord for getting muted so its the best course of action, and if they dont like it then its their fault for getting offended too.