Remember, we're here for the kids! Enjoy doing all the "firsts." Just think about what you and your family are giving them each and everyday and how you will change their little lives in such a short period of time. No, some of these people don't deserve to have their children back. But if we focus on all the negative it will only make in harder to help the children.
This wasn't always my view! We went through some very hard times with our foster sons biological mother.

Thank God we never had to deal with dad! After two years of trying for reunification, because that's what the caseworker wanted, not birthmom, she finally relinquished. This was really what was best for our boys. The boys have been on a real roller coaster for almost 3 years. Different family members have come and gone. Our family has been the only constant in their lives. I thank God that He has given us the strength to be there for them. It really has been hard, but who else is going to do it? They recently had a visit with BS who just turned one! I still talk to mom and things are going ok.
I realize that you are just venting. But I thought a word of encouragement might be helpful.
Stay focused on the life you touch everyday. He'll love you for it (someday!)
