Well, an argument can be made that while a murder ruins ONE life and family, what he did has ruined the lives of MANY families.
Intent is also an issue, as has been stated here. An accidental murder, even in the commission of a crime like a holdup, isn't the same as purposefully ruining as many people as you can so you can get rich and live the highlife.
I don't think a financial crime like this should be treated more lightly than some guy on crack killing the dude at 7-11 for drug money, but I agree to give them a magnitude harsher sentence doesn't make sense either.
Unfortunately, sentencing guidelines for breaking laws are often created in a vacuum, without really comparing them to existing sentences for breaking other laws, leading to these disparities.