Stereotype as a job qualification
Security work goes to Black men because employers buy a stereotype, not a skill: tall, strong, deferential, scary. The very prejudice that marks these men as outsiders becomes the thing that gets them hired.
Low-barrier jobs absorb the undocumented
Jobs that need no training and no experience are where undocumented workers land, because employers in them happily overlook official status. The work is cheap and the paperwork is skipped, and the arrangement suits the employer as much as the worker.
Standing jobs pay least
A whole class of work requires the employee to stay on their feet in order to earn a pittance. Being made to stand is itself a mark of how little the job is valued.