Stephanie - There are many songs out there that likely meet your "70's" qualifier. There is also great variation in the nature of rebel songs. Some speak about fighting or specific events, and some speak to root causes in more subtle ways. My personal favorite from the 70's is Pete St John's "Fields of Athenry", which speaks to the famine era and transportation. It was instantly adopted into the Irish folk tradition and remains one of the most popular pub songs year after year.

Enjoy your search.