Humans get many jobs, all across the outskirts of the Galactic Alliance. In the Fringe Territories, laws are enforced based entirely on how useful they are to follow. As civilisation creeps in, the humans creep out before they become the tolerated exception. That's the thing about fringes and frontiers. There's always more of them.
Here on the edge, overlooking a large and ancient Sargasso, is Bodgy Kludge Station. And the humans have lots of jobs there. Not just in disarming the more dangerous wrecks, or making peace treaties with the unbelievably huge spiders that lived in assorted wreck-conglomerates through the system.
Humans also served as 'canaries'.