Ha, wait, what? Opinion pieces don't exist simply as a public service to help readers get the ol' brain juices flowing! They are outlets for rhetoric, striving to convince the reader--and often to call them to action. For this reason, opinion pieces have a moral valence!

An opinion piece which competently and cleverly convinces its audience that good is bad and wrong is right is a deeply unethical thing. And Krauthammer's entire career was spent doing exactly this.