Popular ethics these days is very simple: if it doesn't hurt anybody, it isn't wrong. It's one of those ironies: we don't discuss ethics because it might hurt somebody's feelings, so discussing ethics is seen as marginally unethical -- or at least it is rarely done in polite company.
But "stop before somebody gets hurt" is inadequate on a number of levels. Anger, lust, greed, pride -- even hatred -- are all realities. They are nearly human universals. Leave them to grow, and they will find a way out. And what exactly is "hurt"? "Hurt" can be as subtle as contempt. As hard to measure as the effects of slander. As low-key as undisclosed deceit. As well-intentioned as spoiling the children, putting a mask of kindness over irresponsibility. Neglect is another destructive force not directly confronted by "if you harm none, do what you will". Some of the biggest hurts are registered by someone who is simply absent from loved ones' lives. And in practical use, the evaluation of wrong in terms of "hurt" tends to focus on the material such as physical harm, financial harm, or property damage. There is little recognition given to the harm of enmity, disdain, mockery; little recognition given to the simple fact that we are happiest and most content when we live our lives in stable groups with a sense of belonging; little recognition given to responsibilities to our parents, our mates, or our children. I would not care to meet somebody who did not agree with "harm none" at the most basic level, but it is not nearly enough to build the stable group with the sense of belonging that is a natural human desire.
"Harm none" is also a completely negative way to frame ethics. If someone avoids all negative actions, does that register a zero? Does the scale of ethics have a positive side? Or have we put all the "positives" in life in terms of "do what you will"? Are positives ever registered for building that stable group to which others can belong? What about purging ourselves of bitterness, malice, and anger, and building patience, kindness, and self-control, so that we do not tear apart the fabric of any group to which we belong? Is there a desirable group that can form without love, or stay together without forgiveness?
So from the very beginning, I have to reject "nobody gets hurt" as an adequate definition of ethics.