Answer: Sotomayor brings the audience's attention to the uniqueness of her culture.
In this passage, Sotomayor is highlighting the importance that culture and traditions play in the creation of an identity. That is why her initial definition of Latino is not appealing to her: it is only geographical, and does not account for culture. The mention of "morcilla" is a mechanism to give the reader an example of the subtle cultural details that form an identity.