I agree with you. HOWEVER, she didn't say she comes from Puerto Rican heritage. She said she is Puerto Rican. I don't say that I am Scottish and English -- because I am not. I was born in the USA, thereby making me an American, just like Sonia. Why does she say she is Puerto Rican? Is it because she hopes that it will give her a Hispanic edge? America is a blend of nationalities, and most come here to leave those other nations' rule, seeking opportunity, and they quickly want to be recognized as Americans. I'm not sure why someone who is actually born here wants to be recognized as someone who is from a country where many others flee to come to the US, unless of course, it is to receive some advantage.
Embrace your heritage, but don't get confused. You are an American if you are born in the USA.