Angels can’t be part of the moral universe. Only humans can be. If we go in the direction of the Eitz Yosef, melakhim aren’t moral; they have no ethical language; they do exactly what they’re told. Human beings introduced the realm of the normative or the ethical because, for the first time, it’s possible not to do what you’re told. Animals don’t do what they’re told, but they do what they’re driven to do. Angels do what they’re told. And, in the middle, are human brings who are right in between.
Rabbi Dr. Tsvi Blanchard, “Created Human Being: A Rabbinic Look at the Human Condition” YCT Yemei Iyun 2006 (June 2006: Teaneck, NJ) {http://www.yctorah.org/component/option,com_docman/task,doc_download/gid,191/Itemid,13/}