I have a MBA from a top tier school, but I also have a decade of experience as senior sysadmin for a large academic computer cluster and a large chunk of a Ph.D. in theoretical physics, so hopefully I'll have some street cred when I say this.
I promise you, if Wall Street paid $500k a year to geology majors, you'd see that discipline packed with money-grubbing psychopaths too. You're confusing the body of knowledge, with the people who learn it.
Yes, I know MBA's who are parasitic, narcissistic sociopaths. I also know MBA's who are good decent people with honest ambition and a desire to make their mark and be their own master.
Believe it or not, there are nerds in business and politics, just as much as in computers and physics. I happen to enjoy economics, finance, entrepreneurship, and public policy. A MBA allowed me to scratch those itches.
Saying "MBA's are all PHB's" is like saying IT people are all BOFH's. You're painting with a mighty broad brush.