Some people probably believe in the mission and prefer to work for the organization. Not everyone is motivated by stock options or benefits, etc.
"Preempt threats and further US national security objectives by collecting intelligence that matters, producing objective all-source analysis, conducting effective covert action as directed by the President, and safeguarding the secrets that help keep our Nation safe."
I'm trying to be as non-judgemental as possible and could see that some people might find this mission compelling.
https://www.cia.gov/about-cia/cia-vision-mission-values/inde...
Think of it like the guy in Firefly hunting down the Tam's. He is convinced he's doing work to create a paradise for everyone else, ostensibly in the hope said paradise will never have a need for someone like him.
People who engage with the apparatus do so because at some fundamental level, they have reason to believe the work has to be done, and many take on the responsibility of doing it to spare others of the burden of having to do so.
If you haven't lived or experienced something that's lit that spark, it generally means that someone else is hard at work trying to keep it that way. Some people never experience it, and most of the ones who have had that spark lit that I know tend to hope those around them never do. It changes you. Most I've talked to are non-committal as to whether the change was good or bad, but almost all felt it was their duty to step up.
Otherwise why risk divulging state secrets?