Because she didn't mingle with her classmates, most of the girls in her class saw her as snobbish and disliked her, believing she was just a pretty face with a powerful backer helping her rise like a phoenix. Jealousy ran in some of the women's blood due to Hera's likeability among the men, who appreciated a hardworking beauty with brains.
Most still belittled her and didn't think highly of her due to the scandal that portrayed her private life as wretched. Some even assumed that she was in a hurry to leave to manage her sugar daddies' schedules and cater to all of them.
Hera noticed their judgmental eyes but her schedule was packed, and she had better things to do than argue with them. If they didn't like her, she wouldn't lower herself to become likable to everyone. As Athena always said, 'You can't make everyone like you. Even if there are hundreds of reasons to like you, bitter people will find thousands of reasons not to.'