Are you American? For most Americans ancestry is an important subject (for many complex reasons), though mostly in a casual way, like sports. Which both explains why the author got upset, but also why they shouldn't have gotten upset.
In my limited experience, I suspect the same is true of many other resettled populations--Chinese diaspora in SE Asia, various Jewish communities, etc. Recording and relaying ancestry is a thing that informs their identity, for better or worse.
Recently I moved to Sweden and some Swedish girl told me she doesn't like that East Europeans come to her country and that East European women (she's probably refering to me) are seen as low class and not cherrished in Sweden.
When I got DNA test from 23andme and it says I am 80% Scandinavian despite parents were living in East Europe and that I am from the original Viking linage.
So it had positive effects on my self esteem.
Are people supposed to suddenly take an interest in some place that they've previously ignored, just because they have some DNA that's commonly found in that location?