You are conflating the larger definition of the term "culture" with a specific, narrower one and it's not making the point you think it's making.
Eh, it's a Pavlovian instinct. See the word "culture" in any context, shout "Racism!"
If it doesn't make sense, and people point this out, just double down and shout the same thing but louder.
Yawn.
I agree with him in many contexts that there is a profoundly racist tilt to American culture, and there is a profoundly racist tilt to "tech" culture as well.
But that's not what was being referred to here, no.