Teacher's Unions have their own issues. They protect crappy teachers from getting fired. I read a news article recently that in the past 10 years, the state of NJ has only fired like a handful of teachers for poor performance. Really? 10 years in a densely populated state like NJ and you only fired 23 teachers or whatever?
Of course teachers unions have their issues; any organization representing a diverse group of individuals will. Should more teachers have been fired? Maybe, but I don't know the specifics of those cases. Teachers don't get into education because it's going to be easy or a free ride on the gravy train, unionized or not. They tend to really want to make a difference at a much lower wage than folks at their same level of education and experience make in other fields.
They are often against standardized tests, or having the teachers evaluations based on the performance of their kids test scores. Why not?
The reason they are against standardized tests is because it forces teachers to "teach to the test" - rote learning in a one-size-fits-all box. This distorts curricula and removes any possibility for tailored learning based on the students' actual needs. Further, reward-based funding based on test scores is skewed away from the schools that need money most, because they are operating at a financial disadvantage to begin with.
Dude, a recent poll showed that only about 50% of graduating high school students knew who the first US President was.
Obviously, the system isn't working. Protecting bad teachers, not using standardized tests, not having performance-based reviews and all the other things that the Unions help keep in place, isn't getting the job done.
They may be protecting teachers, but the teachers are there to educate kids. The kids are the "product", and the product today sucks.
The Status Quo, just isn't good enough.