As an American I agree and this was also my reaction to the comment.
There are a number of these things, though. I personally get a little irritated with the way many people here use terms like "Hispanic" to contrast with "white people". To me, "Hispanic" is a wide spectrum of ethnicities but really more of a linguistic, cultural and national/political specifier, with lots of overlap with "white". People who are trying to be correct about this will pull out complicated phrases like "non-hispanic whites" which may be correct but are also clumsy, reflecting the absurdity of the way we categorize this country's social boundaries in the first place. "White" itself has had a fluid definition in the US over time, previously having excluded southern or eastern Europe, Jews, or even the Irish.
I know that in my own recent ancestry I have at least 4 European ethnicities, some of which would have been ridiculed by other Americans in the past. But this nuance washes away and I am a "white guy" which lumps me together with cultures I don't particularly identify with. There is no sense in denying, for example, that I am less discriminated against by appearance than other groups. But I do not think either that there is one homogeneous "white people" living in the United States.