The reason you don't see "free speech" used for those causes isn't because they don't rely on free speech. It's because advocacy for them is so clearly protected as free speech that it isn't even a question. There have been times when that protection was a question in the U.S., like when protesting wars or segregation laws.
Without the right to say something, there is no legal way to organize or to demand any other right.
Edited to remove an unwarranted statement at the beginning of this comment.
Without the right to say something, there is no legal way to organize or to demand any other right.
Edited to remove an unwarranted statement at the beginning of this comment.