I get what you're saying, but there's also the opposite situaton where Americans get criticized for not taking an interest in the broader world, not understanding where they (we) come from, abandoning the culture and traditions, etc.
I think a person is perfectly capable of understanding where they come from and taking an interest in the broader world without any DNA tests. I actually don't think that a DNA test tells one anything about who they are. It merely tells one their genetic make-up. And while the genetic make-up determines what we look like, it does not define the person that we are.
In other news, Castro has now qualified for the September debate. If one more candidate qualifies, there'll be two debates. (I'd have loved to see them all on one stage but on the other hand, I find the idea of smaller groups appealing as well.) https://edition.cnn.com/2019/08/20/politics/julian-castro-qualifies-september-debates/index.html