Diane Ravitch wrote this piece a while ago summarizing why teachers in particular are outraged. The article summarizes the situation quite well.
In case you may not know, Diane Ravitch, is a Research Professor of Education at New York University and has written several books about education. She's going to be on the Daily Show with Jon Stewart tonight to discuss her latest book, The Death and Life of the Great American School System: How Testing and Choice Are Undermining Education. I really want to read this book.
Note: I accept late birthday presents.I highly recommend you catch this segment if you're even slightly interested in how the current education system in the United States fails its students and how this situation might possibly be remedied. I'll be watching it for sure.