I don't believe you fully let them go. During meditation you can let them go you let them go moment by moment but overall it takes many of these moments to fully comprehend and to abolish them. I try to see through the eyes of the people who caused me trauma and understand their trauma. That is the most helpful thing for me is to understand other people's struggles. To have a perspective of where they're coming from maybe they didn't mean to hurt me. It may have been all they know and a better life than they grew up. That's how I deal for now.