The immediate question that comes to mind is: Were Morgan Stanley and Goldman Sachs providing "color" to Galleon on trades their other clients were making? Definitely sleazeball and unethical. OR are their computers somehow rigged with the exchanges so they see trades before other traders do? Definitely sleazeball and unethical.
It's very simple: the traders and managers at Goldman Sachs and Morgan Stanley are too greedy not to cheat.