I'm not a native English speaker, so I might be in the wrong here, but is she using the word "cultural" in a different way than normally?
I actually love it.
It says what the parents feel about the child.
The only reason you might find this "different" is if you don't consider Black culture to be legitimate.
We call this "racism".
...but he's not American?
It's quite a stretch to arrive at an honest question about the use of a word - by someone outside of your own country's culture - to it being equated to racism, merely because it's from a egocentric (American society) point of view.
The world is a lot bigger than just America.
Maybe tone down the racist accusations until you have some qualitative context to use it. Otherwise, if antagonising people that might otherwise be sympathetic to your plights is your end goal, then by all means, carry on.
Unfamiliarity != delegitimization
Your use of the term racism certainly isn’t lending a hand towards others gaining positive familiarity.