The vast majority of people reading and handling classified information are government employees? That's not the case. I was cleared at TS/SCI + polygraph and many many contractors work in that environment.
In the office where you worked. In the office where I work there are zero. Classification levels don't really matter. It is about the nature of the information. Some is simply never shared with non-employees. Some isn't shared with people not wearing uniforms. Well, excepting one or two non-uniforms but they are still government employees.
I was military first then worked for defense contractors for a decade or so. In the areas I worked (several countries including war zones), at the levels I worked (secret, TS/SCI), in the agencies I worked with (DoD, special operations groups, intelligence organizations), I did not experience what you're claiming.