have no moral obligation to act in the interest of others but nature has brought us to the point where trade and reason produce the highest levels of abundance. To deliberately act against this would be unnatural, an abomination, a mutant destined for a short and unproductive life in the eyes of the universe. Nature conserves energy, it works toward efficiency and seeks balance. I don't think it would be in any man's interest to act as a complete sociopath as he would likely destroy himself in one way or another.
"Endless money forms the sinews of war." - Cicero, www.freedomshift.blogspot.com