There are no universal values, we appear in this world in different starting positions, some are better than others. Country, family, appearance, intelligence – some things from the top of my head, which is already a great influence on human’s life. Moreover, I could start talking about genes or permanent disabilities, what has even bigger effect. As we say that every one is different, there can’t be same expectations from everyone, so can’t be same rules. However, we are good at finding patterns, which lead to survival. One’s who are not, don’t survive. So as the time was going on, people, who were killing each other- happened to be dead. However, people, who decided not to kill each other, stayed alive. Alternatively, if somehow most aggressive people, were to survive, we would decide on the rule that murder is good. Even though, this rules often work, they are not universal. In order to take the right decision, we should be considering only our decision, and do what ever we think is right.
I think that there are no thing such as moral fact. It is better to use something like “Most common thought”. However, we can’t say that some kind of action is right in any situation.