The Namesake

Jhumpa Lahiri is the writer of the novel the Namesake, where she writes of these two characters who moved from thier native land Calcutta to the United States. Lahiri begins by presenting Ashima pregnant and in a hosptial telling us what Ashima fears in this new world. How she fears raising this child all alone without any kind of help. So then Lahiri takes us on a journey and explains that Ashima married Ashoke through an arranged marriage and that because Ashoke went through a near death experience decided to move to America to forget about his past. This leads to why Ashima is in America istead of back home in her native land with all her relatives.
Lahiri takes us through this journey first to make us understand where Ashima and Ashoke come form and why they act the way they do around one another. She lets us know about their religion and their traditions and how really confined they are at times. Which leads into the whole idea of Gogol, Ashima and Ashoke's son, who ends up being raised in America which makes him turn back on his culture. Here the story begins and we end up learning the downward spiral Gogol's life has taken as he struggles through his traditional family holdings and this brand new life in America.

Question: Why do some people who are half Americans and half of another race or mixed are at times ashamed of one thier cultures?