These teacher's main concern was the way tenure was going to be enacted.... Like most states, Illinois wants to do away with the current tenure system that allows BAD teachers to keep their jobs. They of course don't want this just like the teacher's union in NJ didn't with their spending of millions of dollars toward billboards and commercials fighting it.
If you are a teacher and want to make money, guess what, you chose the wrong profession. Want more money? Get a job at a private school.