It's something I have never been able to answer.
The great transformation in Christabel's life took place just after she left school.
Although Mike Judge did allow them to use his character, he wasn't actually involved with the show's creation, and Daria made practically no references to Beavis and Butt-Head.
In their hometown of South Park, they regularly face grotesque events that satirize hot topics of the week, from religion and real-world political issues to pop culture and ephemeral fashion trends.