Capitalism isn't the be all and end all of an open society. The fact that it's socially acceptable that an executive at a company like Blackwater can be compared to any other businessman is a problem. (In the specific case of Blackwater, they are well known enough to perhaps be an exception.)
Being a war profiteer, leader of old-style trust that exploits its customers or a peddler of political corruption isn't rationality -- it's an anti-pattern of capitalism.
You're right that it is an anti-pattern of capitalism. However it is possible for an anti-pattern to be completely rational, while having horrible consequences, given the way the system is set up. The consequences might be more clearly unacceptable when you see it with Blackwater, but exactly the same perverse incentives are driving every company.
Being a war profiteer, leader of old-style trust that exploits its customers or a peddler of political corruption isn't rationality -- it's an anti-pattern of capitalism.