Reason for Comparison in Ethnography

"Although difficult to provie, it seems likely that whenever ethnographic description focuses on some aspect of behavior that has been little studied, as weas the case here with the focus on language use, it is apt to deal primarily with how the people in question differ from ourselves." (17).

I found this statement quite provocative, and have found myself thinking about it frequently. I agree that when we meet others or study others, we often want to make comparisons; however, I was surprised that she only focused on the differences. I find that we often focus on both the similarities and differences, which is how we find common ground. I'm curious as to how others, particularly ethnographers, would respond to her statemetn.