Your argument is that people do not teach Race in the same way anymore. I think that your implication is that the previous way of teaching Race was wrong -- however, this very article is making the point that political activism is changing the way that people teach, and politics has certainly affected how we teach Race -- the most politically-charged topic of them all!
So when you say "you are living in the past century", that could be a compliment -- it could say that the author is not being censored or brainwashed by a political orthodoxy.
If you actually want to improve his understanding of Race, I'd suggest providing him with some data that contradicts his statements, rather than just dismissing him as old-fashioned. Because on the other side of that, it implies that you could just be getting lost in a fashion.
So when you say "you are living in the past century", that could be a compliment -- it could say that the author is not being censored or brainwashed by a political orthodoxy.
If you actually want to improve his understanding of Race, I'd suggest providing him with some data that contradicts his statements, rather than just dismissing him as old-fashioned. Because on the other side of that, it implies that you could just be getting lost in a fashion.