In my experience and what I’m assuming they’re talking about above, is that there is an assumption you can’t be from a certain area/country just because you’re not white. You’re automatically labeled a foreigner. My family is from the Dominican Republic but I was born in America. I’m 27 and I have spent less than 2 months of my entire life in DR. I’m proud of my heritage ffs but I ain’t Dominican. I was born and raised in the USA; I’m American, end of story. “Where are you from?” and “Where is your family from? are a perfectly normal questions. Even if someone flat out asked me “What is your heritage?” I wouldn’t be offended but “Where are you really from?” is an asshole/ignorant way of asking. You can’t assume you know where a person is from based on looks alone. TL;DR: It’s usually the way they ask/how it’s phrased that’s offensive.