For the same reason they can require you to have a Driver's License, be able to carry 50+lbs, live in the borders of Maryland, etc, etc.
Having the right to work in the US doesn't entitle you to a job. And there are plenty of reasons government institutions would want to disallow non-nationals a position. The whole point of citizenship is, after all, buying into the system; if you're not "in" your allegiances or potential recourse can always be argued to be limited. Dual-Citizens, such as myself, are in a similar boat for the same reasons (unless they opt to renounce foreign ties).
Just to give some additional information but there are many government jobs or government contracting jobs where you can be a dual citizen, including I believe this one.
I didn’t mean lacking the exact same job opportunities, but having their loyalties be questioned and denied from certain secure positions.
I don’t believe this job actually would be possible as the level of clearance requested is usually denied to dual-nationals (without renouncing, of course).
Having the right to work in the US doesn't entitle you to a job. And there are plenty of reasons government institutions would want to disallow non-nationals a position. The whole point of citizenship is, after all, buying into the system; if you're not "in" your allegiances or potential recourse can always be argued to be limited. Dual-Citizens, such as myself, are in a similar boat for the same reasons (unless they opt to renounce foreign ties).