On going court with my ex in-laws for visitation?

My ex in-laws are emotionally unstable to be around my children. My children's father agrees and sent in his notarized statement to the court. This court battle has been going on since December. Today when the judge asked me if I felt anything could be worked out in a mediation I responded " I wish I could say yes but the father and I both agree that we don't want them around our children." (The father is out of state and out of Country half the time to to working for the military. The judge ordered a trial date to last 3 hours. Why? Both of us parents do NOT want these people in our children's lives and we have also stated that these people (children's grandparents) have slandered us around our children, in front of us. What should I expect and why is this going to trial?