I think the operative phrase in this post is "I firmly believed in homework every night." Over time and with additional information, you altered that belief just as many teachers have. But let's think about where that belief came from: your training, your life experiences, what other teachers did, your religion? I add religion because I have religious beliefs that I have figured out over the years. They have changed and evolved from the religion I was taught. Most importantly, they are personal beliefs which do not impinge on other people. But homework beliefs do. In your evolution as a teacher and a thinker, you held the power to make decisions in many people's homes based on your beliefs as they had evolved at that time. And those beliefs could render your students' parents helpless in the face of what you required them to do. The difference between and religion and a profession lies in training, and on that score, you and countless teachers have been placed in a position where you were expected to use a method for which you were never adequately trained. Did you have courses in homework in your school of education? Did you have adequate access to continuing education courses on the topic? Did the school where you worked, in presenting its homework policy, offer in-service training on the research, theory and practice of homework? I'm sure the answers are no, and that is why you, and many other teachers, have been in the position of acting on your "beliefs" without the benefit of professional training upon which they could be formed.
For more information on Dr. Goldberg's model, read other postings on this blog, visit his website, The Homework Trap, or read his book, The Homework Trap: How to Save the Sanity of Parents, Students and Teachers.