Bullying Prevention Curriculum - How effective is it if the parents are bullies as well??

I have been doing my bullying education and prevention lessons in the fourth and fifth grades for the past month. I have been working with these kids for 4-5 YEARS!!! I have never felt more ineffective than yesterday. Some of the students are so unbelievably nasty to each other. It has now gotten to the point where I am seeing the true colors of some parents as well. How can I help teach children when their role models teach them to act this way? Some of the parents are bullying each other as well as other students! I can't help but feel that I am fighting a losing battle. I am turning blue in the face talking and talking about empathy and respect and I feel like no one is listening at times.

I became a counselor because I love working with kids. I still have to hold on to a little glimmer of hope that if I can help one child, I have done my job well. I felt so defeated yesterday. However, I got up this morning, put a smile on my face, had my coffee, and I am heading off to work. We'll see how today goes...