Sometimes pubescent boys like to talk shit to their dads. Occasionally in this or in other contexts they say things that aren't completely inoffensive and are even kind of stupid.

I have to say, making this into a PSA about social realities as some commenters seem to be advocating, seems misguided to me. Trust me, the kid has heard it in school, and I have never seen a boy that age take well to that kind of lecture. He'll feel patronized at best and he'll know he has something that he can reliably use to piss you off in the future. Now, disciplining him for overstepping his bounds with you personally, sure, that makes sense. You are within your rights not wanting him to act like a little asshole to you or other household members. But it is at bottom an 11 year old who did something stupid and took a cheap shot at his dad for pointing that out. There's no reason based on anything mentioned in the post to believe it's anything deeper than that.

If it matters, I'm the (mixed but admittedly white looking) dad of two mixed (and definitely not white looking) kids, and a former youth social worker who saw a fair amount of intrafamily racial resentment.