Indeed. Investment banks do not make money with some magic computer program that buys low and sells high eight billion times per second. They make money by buying something, "adding value", calling up clients and asking them to buy it, and then taking a cut when they do. In some cases, this has changed the way the world works; consider options.
(In general, it's really not as evil as it sounds. I write software to help price interest rate swaps, and those don't really ring any ethical alarm bells: http://en.wikipedia.org/wiki/Interest_rate_swap
I don't think the Goldman/Facebook thing is particularly evil, either. The government says that normal people can't buy Facebook shares, but normal people want to. Goldman invented a solution to the problem, and will profit from doing so. "Adding value" like this is great when it's a way to sell ads to web 2.0 users, but not when it's a bank? Why?)
