> why do so many in the valley do this to 'MBAs'.

Because every technical person has a story about:

  - "Idea people" telling them what to do and taking all the credit.
  - A non-technical manager setting unreasonable deadlines.
  - A non-technical manager trivializing a complex task. 
  - "Oh we'll just get him/her to write some code".
  - Being treated as if their talents are a commodity.
  - Being treated as if they cannot communicate like other humans.
  - Putting in blood, sweat, and tears into a project for little or no pay.
  - Studying like mad in college while everyone else seemed to be partying 
    (or this could just be me)