The cultures of the world all have codes of conduct, even the ancient ones, and many of these codes predate the writing of the various books of the Bible and almost all predate each cultures first exposure to the Bible.
Where did the Greek Philosophers gain their insights? Did Socrates have no morals? Was Pythagoras lost? Confucius? Buddha? The American tribes? Eskimos?
Much of what is contained in the Old Testament is simply the conduct codes of the ancient Middle East. Some of these codes are commonly found in cultures all over the world, such as the prohibition against murder, but many are unique to the region and were never adopted by anyone else, like the prohibitions against eating pork or working on Saturday. Many are tribal rules, such as the requirement for a man to marry and have children with his brother's widow in order to ensure the survival of the tribe. Much of the New Testament is a reinterpretation of the older Biblical laws from the perspective of a culture that had been exposed to Greek and Roman thought for several centuries.
We have access to thousands of years of religion, history, philosophy, ethics and sociology from all over the world. We can see what worked well, and what didn't work so well, and we acknowledge that many things should never be allowed to happen again, such as genocides, witch burnings and Inquisitions. We do not believe that any group or culture has had all of the answers, and we refuse to be tied to laws that should be abandoned and rules that do not work. Claiming to have all of the answers is a dangerous game, and claiming to be the "One True Path" has led to some of the most horrific abuses and tragedies in human history.
"A man's ethical behavior should be based effectually on sympathy, education, and social ties and needs; no religious basis is necessary. Man would indeed be in a poor way if he had to be restrained by fear of punishment and hope of reward after death." - Albert Einstein, "Religion and Science", New York Times Magazine, November 9, 1930
It is hilarious that the really stupid ignorant fundies need a pastor to them robbing the 7/11 is wrong. Atheists know not to because they have common sense.