I am not a criminal defense attorney. My law partner is. I don't think they're bad people, however. The will tell you they believe in upholding constitutional rights to due process - which is a gate keeping activity for the innocent - and making sure that justice prevails. So, right now in our country, certain people notoriously get light sentences and charges while others notoriously are treated harshly by the justice system. The Innocence Project has exonerated hundreds of people sentenced to life or death. Defense attorneys can be pivotal in ensuring equal justice.
But I tend to trust that the police and the state are motivated to get the right person in cases like this and I could not be a criminal defense attorney because child molestation, domestic abuse and murder is all to repugnant to me and it would be hard for me to be efficient at representing defendants charged with such crimes who I felt were guilty.