It's a pretty accurate movie of college life in some respects. The dialogue feels real, and the characters are pretty likable. Though some say it's too dated, the characters, the commentary on drugs, phonies, and cops is still entirely valid. Fritz the Cat was groundbreaking for its ability to show people that cartoons don't have to be just for kids.
It's also not a movie that is, as many say, cartoon pornography. The amount of sex feels pretty realistic to me, not overboard, and they aren't lame romantic sex scenes that do nothing for the movie, but they're often dark and hilarious. It's doubtful that this film would even be rated X by today's standards. The nudity is pretty poorly drawn, the "drug" use is just smoking weed (although there is a neo-nazi who shoots up), and the loose morals of the film are contestable since it mocks of everything it depicts.
Fritz the Cat is a great film that can reflect on the counterculture of anytime, not just the 70's.