But why stay within an organization he doesn't believe in and finds corrupt?

For example lets say he joined to serve the army or work at Lockheed and Martin, becomes disenchanted with it, decides to be a pacifist, where is the logic of a pacifist staying in the army?

Another example someone joins the communist party, lives as a capitalist and dislikes communism but refuses to dissociate himself as a communist despite his disdain for the ideology.

A guy gets a job with British petroleum or shell, decides he cares about the environment 

Or a man joins an organization, finds out they are a self serving, exclusive enclave of hypocrites, why stay?

I don't get it, I don't get why someone who dislikes X and disbeliefs Y would stay within a group that promotes X and believes Y. 

It has nothing to do with not being a robot, it seems hypocritical to me.  It has more to do with actually living in regards to your beliefs and not compromising.   Isn't that the definition of hypocrisy?