Dean (John Vernon) Wormer - "Greg, what is the worst fraternity on campus?... Who dumped a whole truck load of fizzies into the swimming meet? Who delivered the medical school cadavers to the alumni dinner? Every Halloween the trees are filled with underwear, every spring the toilets explode."
Omega President (James Daughton) - "You're talking about Delta, sir"
Wormer - ..."the time has come for someone to put their foot down and that foot, is me."
The battle lines are drawn. Anarchy Man vs. the Foot of Repression. Even the forces of Anarch have conventions, just very fluid and ever-changing ones. The job of the rock 'n' roll adherent is to keep up with these changing conventions, to be on the edge, riding the envelope as the universe expands.
The Anarchists do appropriate things: throw drunken parties with rock 'n' roll music, smoke pot, lock a horse in the Dean's office where it dies of a heart attack, run amok through the cafeteria eating both edible and inedible objects, ("Don't you have any respect for yourself?"), start a food fight, take liberties with female guests, are voyeuristic, cheat on tests, and wreck the town.
The Authoritarians, conversely, run the campus, control the ROTC, are sexually repressed, pursue the anarchists, go down in flames in the final reversal. Just like the forces of rock 'n' roll vs the Establishment. Rock and roll persists as a cultural entity because it expresses the youthful emotions of liberation. It is a neotenous art form. Rock 'n' roll persists as a commercial entity because adults found a way to make money off of it. Animal House tapped into that same commercial wellspring.
Animal House also points out a very important sociological aspect of the rock 'n' roll revolution. Rebels and Nerds teamed up together to overcome the repression of the Winners and the Establishment. The Winners teamed with the Establishment because it was through the Establishment's system that they had become Winners. The Rebels and the Nerds teamed because they fought a common enemy.
There is another, more obvious reason for Animal House's appeal. It represents everyone's (at least for males) fantasy of what college was like, should be like, or will be like.
"You can't hold a whole fraternity responsible for the behavior of a few sick, perverted individuals. For if you do, then shouldn't you blame the whole fraternity system? And if the whole fraternity system is guilty, isn't this an indictment of our educational systems in general? I put it to you, Greg: isn't this an indictment of our entire American society? Well, you can do what you want to us, but we're not going to sit here and listen to you bad mouth the United States of America. Gentlemen!"