There are many different reasons why people conclude aggression is wrong. Many people agree based on their religious beliefs. Indeed, most religious and moral traditions hold that aggression is wrong. Others agree based on a variety of other reasons including a natural law analysis, social contract theory, economics, or objectivism. Many people simply agree with the basic common decency and mutual benefit that naturally flows from legally prohibiting the initiation of force, fraud, and coercion. It’s the first thing reasonable people who disagree on everything else will readily agree on.
The Live and Let Live Movement does not take a position on why a person concludes aggression is wrong. That a person concludes aggression is wrong is what matters to the Movement. Upon reflection, most people will conclude aggression is wrong and should be outlawed in all cases.
There are also many similar reasons why people conclude encouraging others to be good humans is a worthy moral goal. Again, why a person arrives at this conclusion is irrelevant to the Movement. That a person arrives at this conclusion is what matters to the Movement. If achieving a free, peaceful, and prosperous world is important to you, this is the best reason to agree with the Live and Let Live Principle.