I dont know. Because people have a bad habit of accepting things based on the limited information they have and they like to think that they have found out things.
I speak German, but I am not a German. But because I speak German, it is often assumed that I am somehow German. Actually, it was just my entire high school offering, except Spanish. And then at college, since my major required a foreign language, since I had already learned German, I simply learned more German.
I learned Chinese later, but when I speak Chinese, nobody assumes that I am Chinese. In fact, they often look very surprised and want to know why I can speak Chinese at all.