i believe there are more aspects to ethnography than behavior, so i think it'd be rather more specific than redundant, except perhaps where the word 'culture' would fit better in the sentence than ethnographical. i could be wrong tho, i only took 1 anthro class. some context would help im sure...
No. It's not racist or stereotypical, either. Everything people do is dictated by their upbringing, of which their culture or ethnicity is a large part. Clothing, speech, opinions, appearance, values, etc. It's not as important in, say, a multicultural city, such as London, but it is still important. But in most areas of the world, it is the single most important aspect of who we are, so there's no way that it's redundant, in any story.