Question

women at the department store snickered and glared at the narrator as she walked by how does this detail support the text main idea

Answer 1

Although your question does not give very much context regarding what was happening in that specific piece of literature,

The idea that nearby women were making fun of/snickering at the protagonist in the text suggests that she is not well-liked. It also could suggest that the women who were snickering are the antagonists/ are mean to her.