Gretchen explains the rules of the lunch table to Cady. The rules cover how each member of The Plastics should behave and dress on different days of the week. If an individual doesn't follow the rules, then that person will not be able to sit with The Plastics at lunch that day.
In this clip we have the deputy do a comedic sketch of protecting the Andy by forcibly enlisting two other people who do not want to be part of this action. While it is filtered with comedy, there is the inescapable thought of an organized authority that tells its workers what to do as and subordinates them in a militeristic fashion of nondisobedience. We can take it to the real world context of who and how authority handles protests (riots) as well as the hyper militarization of police in events like: Zoot Suit Riots, Occupy Movement, BLM protests, and the Inserection