I completely agree with your point, but I do wonder sometimes if we need need to start using a different word than racism with culturally rooted racism like this, which I’m starting to think is the most common racism our modern Western world; discrimination not based on someone’s ‘race’ (at least in one definition of the word), but instead the way they behave based on their culture. Maybe a term something along the lines of ‘cultural-ism’.
One could argue that this is simply nomenclature, and that people are being discriminated against either way, and they’d be absolutely right. But it at least seems possible that we are all currently letting ourselves off the hook too easily with our term ‘racism’, as it’s a lot easier (and in some senses actually true) to say “I’m not racist, I’m not discriminating against his person based on their race/skin-color/genetics” than to say “I’m not discriminating against that person on their culture”. If nothing else, to say the latter you at least need to know something about someone the other persons culture, which if we took the time to actually learn and understand, would go a long way to resolving the problem in and of itself!