hierarchy positions are much more political than technical ones, so hackers are picked by skill and quality instead of 'political reasons', in any strict hierarchical organization, the 'rebels' or 'dissidents' or 'opinionated' are gonna be weeded out of positions of power early on, and this serves to maintain, in the upper levels, only people who have the same exact vision and mindset as the people who are already there, be it because they are really strong followers of the institution credo or because they let themselves be molded by it.

Academia, military, corporations all are like this, I believe.