How do individuals change a system that rewards loyalty, secrecy, and praise to higher ups who run with the status quo way of thinking? Shit, I even recognize that if I was put into a middling position at the CIA/FBI/ETC that I would probably forgo several of my personal moral/political positions to keep and progress in my job.
Changes can come externally through art and civil demonstrations of our power, but really, it may be that our best path is the slow one through education, which is slow, and long, and again, very slow. And very painful.
https://www.youtube.com/watch?v=5eqCprXn_UY
If more people were "more like that", and if more of them would manage the "quantum leap" into serious politics, that would still be slow and painful, but at least more than asking for things or offering facts. Don't get me wrong, that is all very necessary and good, but it's not quite enough IMHO.
If only there were not an agency dedicated to the disruption of organized opposition.
It's incredibly simple to disrupt emerging organizations in to chaos when you have access to everyone's metadata. You don't have to assassinate anyone, you don't even have to discredit all of the important nodes, although that's a useful tool. Many of the critical nodes won't recognize themselves as such. Divert them to other interests, personal, professional, philosophical/moral or legal... And a movement sputters and scatters in to emephera instead of transitioning in to an effective force for change.
Social judo is vastly more effective than jackboots ever dream of being.
Even if you think the incumbent is doing bad things, we've been conditioned to believe that the "other side" (from whichever tribe you count yourself) is evil and must be stopped at all costs. Thus, you have to vote against that evil challenger. This, of course, gives politicians license to be exactly one iota less evil than the other guy.
Although it's a complex question, I think a lot of the blame can be put on (A) the entrenched two-party system, since there can never a choice other than your team or the evil team; and (B) gerrymandering, so that what choices can be made over candidates happens in the primaries, which means the choice is made primarily by the most hard-core party members.
The various TLA's in the US are operating as intended.