Of course, we as individuals aren't to carry that out. We are to turn the other cheek. But government has a different role than the individual How odd it was for Christ to have ordered individual Christians to turn the other cheek but then to allow those very same Christians to do the exact opposite when they act as agents of the state. I understand this odd distinction comes from Thomas Aquinas, but he was wrong on other life-issues as well.
Whether you consider it odd or not, the distinction is a biblical one. Jesus forbade personal revenge. The apostle Paul explained that vengeance is the duty of the state (Romans 13:1-4).